HOWTO: Diagnose the Dynamic Oil Pressure Warning System PDF Print E-mail
Written by Vince Waldon   
Sunday, 08 March 2009

 

Do any of these symptoms sound familiar???

 

 

warning_light_animated.gif

“My oil light has started to come on when my car is hot”

 

“The oil buzzer goes on after I’ve driven on the highway for a while… if I rev the engine the buzzer goes off”

 

“My oil light came on but my oil level is fine”

 

“My oil buzzer comes on when the engine slows to around 2000 RPM…. It’s fine at 3000 RPM or at idle.”

Any of the above are telling you it’s time to check out your oil pressure. Note I said “pressure” not “level”… the warning system does not detect low oil level (unless the level is so low the oil pump sucks in air of course).  The warning lights and buzzers may be the sign of broken wires or sensors OR you may actually have an oil pressure problem.  If this is the case you are shaving months off your engine’s life every minute you keep driving.

 

Low oil pressure problems are typical of high-mileage VWs with worn bearings and oil that is hot and therefore thin.  The combination of thin oil and worn bearings means that the oil pressure is marginal at lower RPMs where the oil pump is not spinning as fast as it does on the highway.

 

In order to understand why this happens we need to understand VW's interesting warning system.

 

 Volkswagen’s “Dynamic Oil Pressure Warning System”

 

VW uses an oil pressure warning system that has two sensors.

 

(1)   A conventional low-pressure sensor, usually on the driver’s side of the head. 

 

 low_pressure_sensor.jpg

 

It is normally closed and opens at 0.25 bar.  The car always pays attention to this sensor and when this sensor trips the low pressure light comes on.  This is the sensor that turns on the low oil pressure light when you turn the key to “on” without starting the car.  This sensor is not connected to the oil pressure warning buzzer.  It’s typically blue in colour and is connected to the wiring harness with a blue/black wire.

 

Note that on 16V and V6 gassers this sensor is usually located on the oil filter flange.

 

(2)   A hi-pressure sensor located on the oil filter flange.

 

 high_pressure_sensor.jpg

 

It is normally open and closes at a fairly high pressure depending on engine type ( 1.8 bar  for gassers, 1.4 bar for normal diesels and some turbo diesels, 0.9 bar for MK3 turbo diesels).  The car only watches this sensor when the engine is over 2000RPM and when this sensor goes off the oil buzzer will sound and the oil pressure light to flash.  It’s typically white, grey, or black in colour and is connected to the wiring harness with a yellow wire.

 

Why the compexity?  The idea is that oil pressure that's OK when the engine is idling is not the same pressure that's OK when you're roaring down the highway.  At idle a pretty low pressure is fine, but that pressure would be a big problem at highway speeds.  Hence, a warning system that knows the difference:

 

Schematically, the system looks like this:

  oil_pressure_schematic_jpg.jpg

 

 

 

 

Troubleshooting:

 

Now that we understand the dual-sensor of the oil warning system troubleshooting is pretty straight forward:

- a flashing light, by itself, is the function of the low pressure sensor on the head

- a flashing light and buzzer are a function of the high-pressure sensor on the filter flange. 

- the car only looks at the high pressure sensor when the car is over 2000 RPM.

 

Troubleshooting steps:

 

1)      Warm the engine up to full operating temperature (rad fan has cycled at least once) and then shut the engine off.

 

2)      Turn the key to “on”; the oil pressure warning light should come on thanks to the lo-pressure sender on the head.  If the light doesn’t come on there’s a problem with the lo-pressure sender, the wiring to that sender, or the dash cluster. A test light between the sensor and the positive battery post should light when the car is off and go out when the car is idling, if the sensor is ok.

 

3)      Start the engine… the oil pressure warning light should go out.  This tells you the engine has oil pressure appropriate for idle. If the light does not go out you have low-pressure sensor problems or oil pressure problems:  STOP and figure it out before driving away !

 

4)       Slowly rev the engine up to 2500 RPM… the light should stay out and the buzzer should be quiet.  If the buzzer sounds you need to troubleshoot the hi-pressure system:

a.      Disconnect the wire to the hi pressure sensor on the filter flange and let it dangle.  The oil buzzer should now come on above 2000 RPM

b.      Now ground the yellow wire and rev the engine past 2000 RPM… the buzzer should not sound.

c.      If you fail either of these tests you have sensor issues, wiring,  or cluster issues.

d.      A test light between the sensor and the positive battery terminal should be off at warm idle and come on as you rev the engine, if the sensor on the flange is working properly. If the buzzer still sounds with the wire to the sensor grounded the problem is most likely the wiring to the cluster or the cluster itself.

 

If you have a diesel:

 

As you now know  the cluster needs to know engine RPM in order to tell which sensors to monitor.  If you have a diesel the cluster reads RPM from the W terminal on the alternator.  If that signal is missing or erratic, your tach will be doing funny things and so will your oil pressure warning system.  Often oil pressure buzzer issues show up at the same time as a tach issue.In particular, if your tach reads too high it may trick the cluster into expecting the oil pressure to be high as well, and the buzzer will go off.

 

I seem to have low oil pressure… what can I do ??

 

The first thing to do is to confirm you really have an oil pressure problem.  A cheap oil pressure gauge (Napa, Autozone, Canadian Tire, etc) connected to the oil filter flange will let you measure the one specification VW gives:

 

  • 2000 RPM
  • oil at normal operating temperature (rad fan has cycled once)
  • 2 bar (29 psi) minimum

 

<picture of cheepo gauge>

 

Note that the test spec is given with the engine hot… get out there for a spirited drive and bring your engine all the way up to full operating temperature before taking an official reading.

 

If your oil pressure is almost OK (ie gets dodgy around 2000 RPM) there are a few things you can try to buy yourself a little time:

 

  • switch to a thicker oil… something like a good 20W50 for summer driving (if you live in a reasonable warm climate) or a wide range synthetic... something like a 5W40 or 5W50
  • ensure you are running a quality OEM (Bosch, Mann, etc) filter … the cheap ones (particularly the one in the orange can) are known to not flow as well as stock
  • check to see if your engine is overheating and therefore overthinning the oil

 

If these bandaids don’t do the trick it’s time to break out the wrenches:

 

  • pull the oil pan and check to see if the oil inlet screen is clogged with crud
  • remove the oil pump and check for wear… the Bentley manual shows the procedure which uses feeler gauges to measure a couple of key wear points.  In truth they very rarely wear out… they are a robust design and are the best-lubricated part of the engine, but it’s only two bolts to confirm.  I personally don’t recommend arbitrarily replacing the oil pump at the first sign of oil pressure trouble… as I say they very rarely fail.
  • Tear down the engine and replace the main and rod bearings.  Although not recommended, this can be done with the engine in the car after pulling the oil pan.
  • If you have a diesel the intermediate shaft bearings are a common wear area due to people overtightening the timing belt, and they can cost a lot of oil pressure when they start to flake.  For all intents and purposes the engine has to come out to replace the intermediate shaft and bearings if you have a transverse-mounted engine (Rabbit, Golf, Jetta).  Folks with Quantums and Foxes can evidently get to it without pulling the engine, as per the comment below.

 

 Summary Table:

 

function location wire colour sensor colour pressure P/N
low pressure sensor head black/blue blue 0.25 bar 028 919 081 D
           
high pressure oil filter flange yellow white 1.8 bar 056 919 081 E
      black 1.4 bar 068 919 081
      grey 0.9 bar 068 919 081 A

 

<end of HOW-TO>


Comments (45)Add Comment
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written by Spokerider, July 02, 2017
Vince,
Thank you for sharing your vw knowledge! Your articles are very helpful for those troubleshooting our own vw-related problems.

My question is regarding a 1995 Golf with aaz diesel engine and the oil lamp / alarm on the cluster going off after driving the car on the hwy for 2 hrs plus, on a 25 degree C day. This happens only when the car is at idle and goes out when i gently speed up the engine rpm's. This is the 1st time I've had this oil warning alarm and lamp go off.......never on the 1hr daily commute I do.

Now, the cluster is not the correct one for this diesel car...I swapped in a cluster from a gas vw, as both the tach and the speedo were non functioning. With this gas cluster, the speedo works but the tach does not. The needle goes hard-over, as far as it can go and just sits there for as long as the engine is on.....from idle to any / all rpms. I know that engine rpm AND oil pressure factor into the alarm going off. Could the fact that the tach is not functioning [ needle hard over ] be simulating a condition of higher rpm than it actually is, and thus triggering the low oil pressure alarm?

I don't have any mechanical gauges like an oil pressure gauge at this time, but may install one soon..... So far, the engine temp has not climbed past 90 C as per the cluster temp gauge.

One last note.... I did add 1 can of Sea Foam oil Treatment to the oil on the last oil change. It is still in there. Perhaps it has thinned the oil out somewhat, and with the heat of a hwy run, the oil is simply too thin......


I just bought this car, have pinned the crank, replaced timing belt sprocket and crank bolt, installed clutched alt pulley, replaced front crank seal, set pump timing, flushed cooling and replaced coolant with VW product, and a bunch of more stuff..... It has just over 200,000 kms "total" on it.

Thank you for your thoughts!!!

Hi there...

Yes I would get a proper oil pressure gauge on the car ASAP, take it for a nice hard test drive so the oil is hot and thin, and then see what the corelation is between the actual oil pressure and the warning bell.

One possibility is that the oil pressure is on the edge of being low, and so when it's hot and thin (the Seafoam will make this worse, too) and the RPM is low the pressure drops below safe.

That said, the same signal from the alternator that drives the warning system also drives the tach... so your problem may be electrical instead.

Either way, an oil pressure gauge is probably your quickest and safest way of narrowing things down... at least in my humble opinion. smilies/smiley.gif smilies/smiley.gif

Cheers,

Vince
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written by Jed, November 05, 2015
I have a 96 GLX VR6 Jetta. My oil lamp comes on and blinks every once in a while. When I rev the engine around 3500 RPMs it stops. Oil also seems to be leaking at a slow rate. But when I check it it says I have enough. Idk what the problem is. What can I do?

Hi Jed... my suggestion would be to follow the steps as outlined... you're trying to narrow down a sensor issue vs. an actual oil pressure issue and I find that doing things step by step helps make things clear.

HTH,

Vince
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written by Chris Rowe, October 27, 2015
Does this apply to all VW's?

I have a 96 TDI Passat wagon. The light/buzzer have started coming on every once in awhile, mostly on the highway after driving for a while. If I take my foot off the gas the buzzer usually stops right away, and then I can keep driving again normally.

If the issue only happens intermittently, does that mean anything? I am assuming that if I can't reproduce the buzzer coming on then running through your tests won't tell me much.

Thanks

Hi Chris...

Actually your symptoms sound pretty typical... low oil pressure (or a malfunctioning warning system) typically starts to show after highway driving... when the oil is at its thinnest and bearing clearances their greatest.

The usual question remains, of course: is your engine starting to develop low oil pressure or do you have a sensor starting to get twitchy?

The only way to know for *sure* is to get an oil pressure gauge and monitor the pressure, on the highway, when the buzzer rings.

Other folks shotgun the sensors, or change to a thicker oil viscosity to see if that changes the symptoms. Changing to a thicker oil increases the oil pressure a bit so may help for either root cause.

I had an 86 TD with 400K km that started to develop low oil pressure after a good highway run... changing from 10W30 to 10W40 upped the pressure just enough to keep the buzzer off for another 50K or so. The car definitely had bearing wear but no other symptoms, so the goal was to keep the pressure in the safe zone, even on the highway.

HTH,

Vince


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written by Brendon, August 16, 2015
I changed my leaking oil pressure switch and now the light and beeping noise does not stop. It usually takes a couple of minutes to come on. I even tried to put the old switch back and the problem still occurs. Any advice will be aprreciated



Hi Brendon... the usual cause of what you describe is someone selling you the wrong replacement oil pressure sensor. Per the HOW-TO here the system has two different switchs... one is normally open and the other is normally closed... and if the wrong one gets subbed in problems happen. smilies/smiley.gif

My suggestion would be to follow the troubleshooting guide steps to confirm that the sensor is the issue. You could also double-check the part number of the switch you installed.

Hope that helps,

Vince
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written by Chris Harris, June 04, 2015
Need to know if this is the same as the depressed engine failure warning. While driving the vehicle shuts off in the middle of the road then sets for about 30mins. starts right after again!


Hi Chris... I'm not aware of any vehicle... and certainly not any VW.. that shuts itself off for 30 minutes due to low oil pressure. Stationary industrial engines certainly, but I can't imagine any car manufacturer taking the safety risk.

My guess: your problems lie elsewhere. smilies/smiley.gif

cheers,

Vince

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written by manny, June 03, 2015
hi guys!
this is what happended to my Audi A3 1.6 petrol 1998 vintage the otherday. The vehicle had recently been serviced only to months ago and motd. At a cost of £1000.
The oil level warning light came on then went out, then the buzzer came on then went out. then the engine revd very high. Even after stopping the car and removing the key, the engine would not stop for some considerable time. and with the associated bearing ends knocking noises.
I am now faced with a bill of £4600 for a replacement engine, due to an oil pump failure. although i recently had this engine serviced by the main audi agents no one said i should change the oil pump. Had they done so i would have done so. so why dont manufacturers fit oil pressure gagues to motor vehicles these days? This is bad engineering practice, its only a gague that tells you what an engine is doing, not buzzers and lights. i had only checked the oil level before starting the journey, so knew the oil level was fine.

I am told the car is so old, there are no spare engines in theUK, and have to get one specially made in Germany. And have it shipped over in 10 days time. All this for a hapeth of tar and oil pump. i intend to fit an oil pressure gague to the new engine when i get it and maybe all so an emergency external electric oil pump. this practice is done on marine engines for years. never just relying on one pump.
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written by Kevin Toney, November 14, 2013
Hi, Thanks so much for your informative and useful "How To" on the VW oil sensors. I have a '97 Canadian turbo-diesel Golf.

My High Pressure sensor seemed to go out this summer. My mechanic said that he checked the pressure and it was fine. [Don't have actual numbers.] Any way he replaced the sensor on the flange and most of the problems stopped. But periodically it went off, and then would stop for no reason. Other times, it would go off, but if I depressed the clutch and reved it up to about 4000 rpm for a split-second it would stop.

It was time anyway, so I did an oil/filter change about a month ago. [5/40 oil] Well since then it hasn't gone off at all. Then this week it started back, constantly. Fine below 2000 RPM, but about 2300 it goes off and won't stop until I turn off the key. Reving does nothing. (NOTE: My brake warning light periodically flashes on the cluster without touching the hand-brake. Also, the left cluster illumination light works and then doesn't for a while and then comes back.)

I just found this site, so I haven't had a chance to run any of your diagnostics yet, but does this sound like a cluster problem? I'll certainly contact my mechanic for actual numbers and try to run the diagnostics myself, but I am confused.

Thanks,

Kevin


Hi Kevin... yes it can be a bit confusing for sure.

At this point I don't think you know enough to narrow things down...for example, it would be good to know the actual oil pressure numbers, particularly now, given that it is misbehaving again.

Best bet: follow the steps one by one and it should become apparent where the issue is. Anything else is just an internet guess. :-)

cheers,

Vince
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written by Aboo, November 13, 2013
Hi , firstly , a great article and very helpful indeed.
I think I have a low pressure problem , the light flashes and then goes off when driving at low speeds ( 40 - 60 km/h ) , however when i pick it up and drive at 80 - 100 km/h , then the light stays on permanently. Is this a bad sign , simply a bad switch ( on the block ) or oil pump change or just a blocked oil filter.
What do I do.

Hi Aboo...your problem could be any of the things you list...if you follow the instructions step by step as listed you should be able to track it down.

cheers,
Vince
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written by Chris Brown, September 04, 2013
Vince. Thanks for very well engineered article.

Chris
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written by Steve, August 09, 2013
In your section regarding If you seem to have low oil pressure, the instructions say to check the oil pressure at the oil filter flange (high pressure side). I also subscribe to Alldatadiy.com and their test procedure says to test using the port on the end of the head (low pressure side). High pressure side reads 20 psi at idle and 50 at 2000 rpms. Low pressure side reads 15 at 2000 rpms.
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written by Geoff, July 15, 2013
Hi Vince,
Re: the 89 Cabriolet (June 18th), I found the problem. The last cam journal is very worn and gushing oil. I blocked its oil port and checked the head pressure by turning the oil pump shaft (with distributor removed) with a drill attachment. The pressure is over 60 psi.
So, unless you know of some fix, it looks like a new cylinder head (why did they make these journals without bearings?). Do you have any recommendations for remanufacturers? or good used heads? One site I have looked at is RAM remanuf. heads in St. Louis.
Thanks so much for the time you put into this. Geoff



Hi Geoff... can't really help you with a St. Louis source of a 1.6 head... but I can tell you that unless the cam journal is deeply gouged a good machine shop should be able to align-bore the camshaft journals and make the cam seal again like new. They would do the same thing if the head was warped: remove a bit of material from the cam journal top (which makes the hole in the middle smaller than it needs to be) and then align-bore up the center to return the cam journal to its proper size.

Might be worth a call or two? HTH!!

Vince
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written by Geoff, June 18, 2013
Hi Vince,
I have an '89 Cabriolet, 1.8L gas with oil pressure problem. With a mechanical gauge, at temperature, I have 80-100+ psi at the high rpm pressure port and 5 or less psi at the head (low rpm sensor port). The lifters are clacking, so I know the pressure is too low. Does that great a pressure difference sound like a blockage, or worn intermediate shaft bearings (gas does have intermediate, yes?) The low pressure light first came on after the engine ran a little hot because the fan was out. Before this, the pressure ran a little above 1 bar on the cluster gauge with 20W50, so something in the gally was wearing. The main and rod bearings are brand new. Thanks, Geoff

Hi Geoff...

IMHO you've done a very thorough job of troubleshooting and yes...like you the huge pressure differential between the high pressure port (the beginning of the oil galley) and the back of the head (more or less the end of the galley) suggests worn bearings. Since you'd done the main and crank that pretty much leaves the intermediate shaft which on gassers drives the distributor iirc. They are a common wear item on diesels due to the high tensions on the timing belt, but I suppose there's no reason they couldn't wear on high milage gassers as well...just never heard of one going.

It's generally the sprocket-side bearing that wears and it can be checked for flaking wear with the engine in the car. Sadly the engine has to come out to replace the bearing, if that's what the issue ends up being.

If you go to www.vwdiesel.net there's a couple of good threads on IM bearing checking/replacement... you'll need to make a puller/installer.

I wish I could think of something else it could be...but you've eliminated all the usual (and easy to address) candidates. :-(

I suppose you could try a really high-strength oil sludge remover just in case it's a sludge blockage somewhere... but I suspect you'll have to at least inspect the IM shaft bearing.

best of luck,

Vince
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written by BobFox, May 16, 2013
I bought a used 1.6 CR diesel for my Rabbit Caddy. It started good and ran good, but I could see a little bubbling on the left rear corner of the engine. It overheated at an idle for a few minutes when the fan didn't come on, but didn't boil dry. After it was, however, increasingly hard to start. Finally I'd have to crank the engine until the oil pressure got up to 60-80 and it would start. Took the head off, found no damage or warping. Changed the head gasket and bolts, etc. Put it back together and now have 0 oil pressure in the head! Took the pan off; took the pump off, and took it apart: no sludge, clean screen, pump seems to be fine. Loosened the oil filter and oil squirts showing it's pumping. The return is good because I refilled the oil from the top. I have a working oil pressure gauge connected to the head. In summary: I had warm oil pressure of 20-80, changed head gasket and now have 0 oil pressure in the head. I'm baffled.

Hi Bob:

Can't tell from your post if your head has solid lifters or hydraulic, but the number one reason for no oil pressure after a head gasket change on a solid lifter head is putting the head gasket on upside down. The gasket looks like it's unidirectional, but flipping it over blocks a small oil feed line to the head... and blam..no pressure. :-(

If you've got a hydraulic lifter head (you'll know 'cause it has the extra drain channel and the gasket can definitely only go on one way) then not sure what happened...perhaps some old gasket got into the oil passage?

Either way, sadly at this point the head is probably coming off again. As you probably already know the head bolts are single use.

Hope you figure it out... best of luck!

Vince
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written by mike, January 20, 2013
i have a 1994 jetta i put a mechanical pressure gauge were the oil pressure sensor is on the the side of the block. I have 10 psi when the car is warmed up and idling. Is this normal? If not what is normal?

Hi Mike...unfortunately VW does not publish "normal" pressures at any RPM other than 2000...so there's no idle spec.

Having said that, 10 psi per 1000 RPM is a reasonable guideline lots of VW folks use, so if you've got 10 psi at idle, with hot oil (your engine at normal operating temperature)... particularly if where you're measuring at the head sensor... you're probably fine.

Cheers,

Vince
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written by michael, September 21, 2012
I used your guide to troubleshoot mine. I had 44 PSI at 190 Degrees and 2,000 RPM so I wasn't worried about the light, but I didn't know how VW tied it all in.

I have a 1996 TDI (1Z) passat station wagon (a bit of a rarity), I didn't see the one on the block, and there are two on the oil filter housing. Is mine a little different?

Thanks

Hi Michael... yup on later models (and some earlier 16V engines) VW started to put both sensors on the oil filter flange. Eventually they deleted the second sensor all together. ;-)

cheers,

Vince
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written by Nuno Lima, July 08, 2012
Hi there, thanks for the answer.
I have yet to check the cables and dash.
I understand the bearings part, it now makes sense that it can be that.
Just have another question, which you don't mention here.

You say the car only watches the high press sensor @ 2000 rpms and above.
What does it mean then, when my car still continues to buzz and flash when the car is stopped and idling? Shouldn't it stop? It has happened 2 or 3 times.

Cheers


Hi Numo...what you're describing suggests an issue with the warning system in the cluster, since the buzzer shouldn't sound below around 2000 RPM.

cheers,

Vince
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written by Nuno Lima, June 21, 2012
Hi there, I hope you're still answering this.

So, I have a VW Golf mk3 1.4 GL that has this problem.
After the car is running for a while, light and buzzing goes off: If I accelerate past ~2200 RPM or if I shift down it stops. This has happened in both low and high gears.

This has been going on for some months now and many things were tried, with no result:
Sensors were changed. I don't know the brand used tho. Some argue non VW ones don't work correctly.
The system was cleaned, including the oil pump which I know recently replaced it, thinking it could be worn out.
Doesn't seem to be burning oil. No white/blue smoke, just the normal.
The car was overheating, because the fan was only starting to cycle really now. It is now fixed and car is usually at 90º.

I've yet to check if there's any faulty cables or even the instruments panel. I have a hard time believing it's this because once it starts buzzing there's the pattern I mentioned above.

However, how it starts buzzing seems random.
Like I said, it takes a while to start doing it, but, for example, the other day, I went for a 1 hour drive, lots of curves and ups and downs, it buzzed even in 2nd gear and I think it was above 2300 rpms. When I left those complicated roads and went home, it didn't come off once, and it was a 20min ride home. I tried to get rpms as low as possible without the car dying, tried to get those rpms high, and nothing made the buzz go off.
Also, yesterday, I made a 2h30m 200km trip. Mostly highway. Same buzz pattern, however, as time went by, it seem to stop buzzing in higher rpms than before, perhaps as high as 2600-700, while before it stopped right at ~2200. And it even continued to buzz when stopped at toll booths. In that situation I would press the clutch pedal and rev up the car and it would stop for a while.

So, could it be bearings? If yes, how would that affect the engine performance? It is running really well, with a great heart, and, wouldn't worn bearings be burning oil like mad?

That's all for now I guess.

Thanks

Hi Numo: per the HOW-TO you really need to get an oil gauge on there and see what's really going on.

Given the age of the engine and the fact that you said it overheated my guess is that you do in fact have oil pressure that's on the low side...so when the engine is hot and RPMs are low the alarm is triggered.

Bearing wear causes low oil pressure because they present less of a restriction to the oil gallery... but they don't cause the engine to burn oil because they are not in the combustion chamber.

If your gauge confirms your pressure is on the low side you can pull the oil pan and check a couple of the main bearings from below, using Plastigage.

cheers,

Vince
...
written by justin freed, June 10, 2012
“The oil buzzer goes on after I’ve driven on the highway for a while… if I rev the engine the buzzer goes off”

This was exactly my situation. I replaced both sensors (not recognizing that the low oil pressure was not connected to the buzzer)with the same result. I took out the cluster and tried to isolate the "buzzing" component to no avail. Then, I found your site and "Yippee" - I figured it out.

After testing to ensure the actual oil pressure was okay, I grounded the "yellow" wire (eliminating the buzzing) and then installed 2 oil pressure gauges - one for low and one for high. Now, everything runs fine and my "cockpit" is starting to look more and more like a plane smilies/cheesy.gif

Thanks for your help!

Hi Justin... thanks for your kind words. Yup...a very common problem as these wonderful cars start to age... and as you found out not the end of the world to troubleshoot!"

cheers,
Vince
...
written by steve, April 18, 2012
Vince, great write-up. I have a 95 Passat VR6 GLX. Weird problem started occurring shortly after an oil change. Oil Pressure indicator started going off when I was driving about 10 mph (ie way below 2000 RPM). Brought it to the garage, they said pressure was fine and everything seemed alright & they could not replicate the problem. This happened again the other night when I came off the highway doing about 65 mph, came off the highway and about 5 miles after that the buzzer started going off, again I was doing about 10 mph when it started going off. So I brought it back to the garage and they decided to give it an oil change just to see what would happen... they put a new Napa Gold filter in it. My question would be... if the psi seems ok at idle, 1500 & 3000 rpm, and the garage insists that the sending unit isn't leaking or faulty, what could be the issue? Would a cheapo filter send this warning sound & light off? Thanks. - Steve

Hi Steve... thanks for your kind words.

As always I think the important first step is to figure out if you have an actual oil pressure problem. The garage is reporting the pressure as "fine"...are they able to tell you the actual numbers, with the oil hot? 10 psi per 1000 RPM is about what you should see. If it's a bit low yes I would yank out the generic NAPA filter and get an OEM German MANN or Bosch... not much more expensive and guaranteed to not cause you problems. The generic ones have been reported to sometimes not flow enough and trigger the sensor.

If the pressures are fine then it's most likely a low pressure sensor issue (since your cluster isn't doing anything weird like ringing the buzzer below 2000RPM) and so I'd be inclined to just go ahead and replace the low pressure sensor on the driver's side of the head. Again I'd recommend getting the proper OEM part... they are cheap.. and make sure the one you get is proper one, per the color chart in my HOW-TO.

cheers,

Vince
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written by Martin Dixon, February 28, 2012
Hi Vince

I have a VW Golf 08 Plate 1.4l, mileage 50,000.

I am not clued up on cars, so i have to apologise if this doesnt make sense. I noticed the light and buzzer one day last week. I checked the oil level, and all was fine. I therefore put my problem into google, and suspected it was the sensor. I have since had a new sensor fitted, and still the buzzer and light come on and off. The buzzer/light does not appear on the motorway, unless i am slowing down, and tends to be on and off when i am driving on the road. Please can you help?

Hi Martin... the symptoms you're describing are exactly what this HOW-TO was designed to address. Follow the steps above (or get your mechanic to follow 'em) and you should be able to figure out where the problem lies.

In general, if the buzzer comes on only at low engine speeds and after the engine is warmed up it's generally an authentic low oil pressure problem as opposed to a sensor or wiring issue, and a mechanic's help will be required to diagnose further anyways.

cheers,

Vince
...
written by Jane Paverd, January 25, 2012
Hi, I have a 2000 VW Golf 1.6i. In November last year my car's oil light came on with a buzzing sound when driving. It normally happened when I had just started driving, mainly in the morning and then it would happen in the afternoons as well. I had my oil pressure checked which was fine so the switches were replaced. I had no problems until this morning, after I filled my tank with petrol and drove about 800m the light came on the buzzer went off about 10 times. Do you think I have faulty switches??? Thanks Jane

Hi Jane...

As a quick guess, if the buzzer has started to come on only after the engine is hot and RPMs are low its likely to be a pressure problem... if it happens when the engine is cold as well more likely a sensor/wiring problem.

Given that your symptoms have returned you may have to start from scratch...have your oil pressure checked at 2000 RPM when the engine is nice and hot (worst case scenario) and if that checks out run thru the tests in the HOW-TO to see if one of your new sensors has gone.

cheers,
Vince

...
written by Steve, December 17, 2011
Hey Vince! Great how to.

I'm in the middle of diagnosing two problems in my new mk2 1.6 td. I have a fuel starvation issue that I'm hoping to have solved tomorrow. But also, I have low pressure sensor going off at idle.. but only at low idle.. like 700rpm. Little turn of the fuel screw and idling at just over 1000 it went off. Also, when I was driving the car home from 2000-2500 rpm I would get buzzer and light blinking but would go out when revved or if car was driven at 3000 rpm. I bought a direct mount m10 oil pressure gauge.. can I just screw this right into the side of the cylinder head and also into the oil flange (if nothing is in the way)? If that won't work can you recommend a type of hose so I can screw that in instead and have it a few inches out?

Hi Steve...

The threads are M10 so your oil pressure gauge will screw in properly...but as you point out there may be something in the way. Most auto parts stores (Autozone, NAPA, etc) sell oil pressure gauge installation kits...a length of nylon hose and several different adapters, one of which is generally a 1/8 27NPT which is very very close to M10 and will work just fine.

cheers,
Vince
...
written by Cari, December 05, 2011
Hello, I have a 2006 Audi A3 Turbo and I recently was driving and the oil pressure light and buzz went off in the center area of the dash board. I took the car in to an Audi garage and they kept the car for 2 days. Upon picking up the car they advised me they could not find anything wrong with the oil pressure, they checked everything, drove it for 4 miles and no light came on, and I was charged $180.00 for the diagnoses. When I went home (San Francisco) the light and buzz came back on and turned off. The light does not stay on. It comes and goes. But I was shock! I would think the first thing the shop would have done was check the sensor's? I took the car back to the shop today, but what should I do? Please HELP!

Hi Cari...my suggestion would be to follow (or have a reputable shop follow) the instructions in this HOW-TO...in my experience there's no substitute for step-by-step troubleshooting, particularly when the health of your engine is involved.

cheers,

Vince
...
written by owen, November 24, 2011
My light and buzzer come on when i am below 2500 rpm. I've replaced both sensors and oil pressure is normal. So what do i replace in the cluster, and is there any type of bypass?

Hi Owen...since it's a "below 2500 RPM" issue it's related to the low pressure circuit, which generally is not supposed to invoke the buzzer... so yup it sounds like the cluster circuitry is the best suspect. You don't mention what year of car you have but on all the MK2 and MK3 clusters I've seen the oil pressure warning system is just part of the cluster's circuit board... perhaps you're off to a junkyard? You could probably find the buzzer and delete it, but the light would still be on.

cheers,
Vince
...
written by Tom, November 20, 2011
hello i just bought a jetta mk3 95...while driving it home the oil light was flashing and buzzing at about 2200 rpm's when i revd it, it stopped flashing and buzzing...then it will hesitate and bucking.....when i was driving slow in second gear through a lot i had to shift to second gear cuz no matter how far i pushed the gas petal it wouldnt go im confused with all the problems and your hi pressure and low pressure sensor testing because it was similar but didnt know which one to test

Hi Tom...in around 2000 RPM is where the transition occurs between the system watching one sensor vs the other, so without further testing it will be tricky to know if this is a sensor issue, and if so which one. If this happens even with a cold engine it's likely a sensor issue... if it's only happening once the engine has warmed up it's more likely that your oil pressure is actually on the edge of being too low (shows up when the oil is hot and thin).

First step, per the guide, is to get an oil pressure gauge on it and figure out if you've actually got a problem or not. If for some reason this is impossible you can shot-gun it and replace both sensors... they are not that expensive... but my personal approach is to proceed scientifically and I usually recommend measuring your oil pressure before blaming alarm lights on wires or sensors.

In terms of the bucking and low power: that's likely completely unrelated to the oil pressure system and you'll need to run thru the gambit of suspects: compression, timing, glow plugs (if this is a cold running issue), clogged fuel system or fuel filter etc etc etc.

Cheers,

Vince
...
written by dave kent, September 29, 2011
my buzzer and oil light comes on around town...i took it about 12 miles earlier that day and it was fine...weather being realy hot...wen got bak to towmchanged my coilovers and dash clocks....i took it two seconds down the road afterwards and it started to buzz and light came on...is it nething to do with the dash clocks iv putr in??? it did flash the light on the mot three weeks ago afta the cat test...but drove it afta and it was fine...?? help ....please..thanx

Hi Dave... per the HOW-TO I'd suggest checking your hot oil pressure with a gauge first and foremost...otherwise you're just throwing parts at 'er.

If your hot oil pressure is OK the wiring steps described should help you track it down if it's a wiring issue.

Vince
...
written by Tom Davis, August 29, 2011
Hi, i'm driving a mk3 polo breadvan 1L. I to have the problem with the buzzer, normally if i'm driving about 30/40 miles its fine but anything over that and the buzzer starts to sound, if i put it into netruel and rev it the noise goes away, I've checked my oil and all is well, the sensors have also been replaced by the previous owner. I am only 19 and currently studing so i'm rather tight on cash, would you recomend me taking it to a vw specialist? or is there anyway i could disconnect the sensors to stop the buzzing? if anyone could help me i would much apreciate it, thanks.

Hi Tom... from your description it sounds like your oil pressure is in fact on the edge of normal...at lower RPMs not quite enough and the warning system sounds the alarm.. rev it a bit and the pressure comes up and the alarm goes goes off.

You said you "checked the oil and all is well"...if by this you mean oil level you should still consider checking the oil pressure, since this is what the warning system is keying on, not level.

The instructions in this how-to pretty much apply to your circumstance.. step one is to check your oil pressure and confirm that you've got the right pressure. If so, you've got a sensor issue and thankfully they are very cheap to replace. Unfortunately engine damage due to low oil pressure is not so cheap!

cheers,

Vince
...
written by Kyle, May 23, 2011
I have a 1992 fox and have the buzzing issue but the question i want to ask is, could the problem be because i dont have any oil pressure sensor on my oil filter flange? On upon starting, the light and buzzer stays off. Even whilst driving for a short period, but once i drive a longer distance, the buzzer comes on. Sometimes it goes off after takin my foot off the accelerator and putting it back on but once the buzzer stays on, the only way i can get it to stop is if i rev my car above 2500 RPM's. Even with that though, after a while, the buzzer eventually stays on. Would be appreciated if you could guide me in the steps i have to take in order to fix the problem.

Thanx


Hi Kyle...I am not directly familiar with how the Fox warning system is designed, but if there's only one sensor the buzzer is probably just part of the usual low-pressure warning system. The car's telling you it thinks it has low oil pressure... bet bet would be attach a pressure gauge and determine if you really have low oil pressure or just a sensor issue, per the HOW-TO.

Vince
...
written by m lane, April 20, 2011
Hi, here with a mystery. your write up is SO impressive; i came here some time ago when my 87 (gas) golf's higher RPM oil pressure switch started going off when rapidly slowing after a while at highway speeds. read your article, changed the switches, then dropped the pan. *a note: have not done that before* Based on my limited experience, the intake screen looked pristine, hard to find anything that could be called gunk anywhere around. put the pan back on with a gasket and silicone, filled back up with a heavier oil, and ran it for a while on the blocks, then to the store around the corner with no leaks in sight (seemed, from the way it sounded, much happier with the heavy oil). so then i started to drive it to work, 5.5 miles away. all great until mile 4.5, when the low-rpm pressure light went off (for the first time) and i pulled over to find basically NO oil in the system.
had it towed back across town and asked my mechanic to redo the pan installation since obviously not worth the destruction of the engine (if it had anything left, poor car) to perfect my mechanic skills. But then he said the pan installation is fine, it's not leaking, didnt look like any silicone had slipped in, and the leak was in the pcv system. he showed me all the sheen over there. but i should emphasize that i would call it more like a dump than a leak: 100 to zero in a mile or two.
So then he has been trying to figure it out and no luck. he checked the compression and it was 150 all the way across. one thing i had worried about, what they're calling the oil intake baffle, which is different than a lot of baffles, i had broken a couple of the 4 clips than hold it on to the intake, but he said it was still attached in place when he was there. he's a fabulous, trustworthy guy but usually works on american cars so he also asked 2 people he knows who work on vws and everyone is out of ideas.
Do you have any thoughts i could investigate? i feel that it MUST be somehow related to what i did with the pan. Thank you for all your gorgeous information.
-m
...
written by Karl Snyder, March 27, 2011
My high pressure oil buzzer just started coming on today! So just to be sure, I ground my high pressure sending wire and the buzzer does not come on at any RPMs. I hookup a test light to the high pressure sender and the light never comes on as the engine is revved to 2,500 + RPMs. This would still be indicative of a bad high pressure sender? Would it matter what oil filter I'm using? I'm running Castrol 20w50 with a Wix brand filter.

Hi Karl... yes, it sounds like your high pressure sensor is defective, but as per the HOW-TO the only real way to be sure is to hook up an oil pressure gauge and find out. Same goes for any possible impact of different oil filters etc.

Vince
...
written by VW Petrolero, October 21, 2010
I have a 93 VW Golf TD that I replace a used Fuel Pump due to a rusty previous one.After I started up the oil light was blinking at idle or High Speed ,replaced lower pressure sensor and no diference,the sensor when I start the car it connects to ground and the upper one by the cyl head interrupt the ground when engine starts .So the sensorsare OK .Even disconecting both the light still blinks.
I had the battery disconected.In other forum somebody mentioned something about the battery disconecting might make the light blink .Is there any relation ?.
Thanks for your help

Hi there...

If you've confirmed that your sensors are working correctly and the wiring is fine then the only thing left to suspect is the cluster itself. MK3 clusters are well-known to have all kinds of freakishly bizarre issues unfortunately, and I've never heard of an oil pressure light issue going away by unhooking the battery unfortunately. Finding another cluster to swap in quickly as a check might be a good next step.

Vince
...
written by Jason, October 18, 2010
I think these should be added to the part number table. They're the sensors for the oil pressure gauge that comes in VWs and Audis.
0359195610-5/0.3 Barwhite pressure sensor for oil pressure gauge/warning switch, 2 pinM10x1
035919561A0-5/1.8 Barblackpressure sensor for oil pressure gauge/warning switch, 2 pinM10x1

The black one is used on all Audis, it combines the high pressure warning and gauge sensor. The white one is from Cabriolets and other VWs with oil pressure sensors, it combines the low pressure and gauge sensor.
...
written by chris, August 07, 2010
Hey, nice write up.
I've got an 84 diesel Jetta and the oil light and buzzer seem to have a mind of their own. The light will blink sometimes, the buzzer will go off, and off and off. If I wack the dashboard, or hit the horn it will often stop the buzzer. I've taken the instrument panel out thinking it may be an electrical issue in there. Any ideas what to look for?

Hi Chris...thanks for your comments.

Since mechanical change ie hammering the dash is leading to a change in the symptoms I'd certainly be inclined to suspect loose connections somewhere. After 35 years there may be some loose solder joints on the cluster or some corrosion between the cluster and the harness plug.

A careful inspection of the cluster's circuit board with a magnifying glass might reveal a solder issue, and a can of electrical contact spray would be a good way to clean up any connector issues.

If all else fails you could try swapping in a cluster from a junkyard... even a gasser cluster if you can find one... just to narrow it down a bit.

cheers,

Vince

...
written by Mark, July 24, 2010
Hi Vince, very good explanation, but I have another oil pressure indicator issue.
Car is a Passat B4 TDI.
Normal signalling of oil pressure system is working OK (i.e. indicator lights up with ignition turned, blinks and buzzes when wire from hi pressure switch is pulled), but during a normal driving the oil pressure indicator light (a red LED to be precise) very faintly glows, continously. Do you have any idea where to look? This happens both with a cold and a warm engine. Oil pressure verified OK with a pressure gauge. Please, any ideas?

Hi Mark: it takes very little current to make a LED glow... so it is likely a poor connection somewhere. Since it occurs at all RPMs it's probably on the low-pressure side... does the dim LED glow go out when you pull the wire off the low pressure sensor?? If so the sensor is defective. If not... you can trace the sensor wire along the harness... it may have rubbed bare somewhere and is grounding itself a bit.

Another possibility is the cluster itself... swapping out a known-good cluster is the quickest way to isolate that problem. A bit of moisture on the circuit board can cause phantom current paths very easily.

In the end, if you can convince yourself that you'l see a solid LED for both low and high pressure switches, you may decide to just ignore.

Let us know what you find!!

Vince
...
written by K. Stewart, June 20, 2010
Hi:

Would you be able to clear up some conflicting info on your web site. My 1985-1992 VW Service Manual Section 3:41 says the lower oil pressure switch is on the filter flange and the higher one is on the end of the head. However, on 3:43 there is a picture which shows the high pressure switch at the filter flange. Which is correct??

Thanks

Hi there... yes the Bentley is conflicting sometimes.

The paragraph on page 41 of chapter 3 that reads "the low pressure switches are located on the oil filter flange (0.3 bar) and the end of the cylinder head (1.4 or 1.8 bar) is in error, in my opinion.

On that same page figure 7.1 shows the higher pressure switch on the flange, and as you mention fig 7.6 on page 43 of that same chapter also shows the higher pressure switch flange.

This has always been the case on any VW with dual sensors I've seem and also makes sense... I'd expect the most pressure to be at the flange just after the pump, with the least amount of pressure at the tail end of the head. It's also the case that previous engines with only one sensor had the 0.3 bar sensor at the head.

All in all... I believe how the system is represented on my HOW-TO is accurate: higher pressure switch on the flange and lower pressure switch on the head.

Vince
...
written by zia, June 13, 2010
Hi recently i changed my oil and than i noticed when i drive over 2000 rpm the buzzer goes on what can i do to fix it im living in small island in thailand and the local mechanics don't know what the problem is after putting a new motor oil and checking the only oil sensors on oil filter , he gave up on me , do you have any suggestions thanks

Hi Zia... if you follow the instructions in this HOW-TO step-by-step you should be able to figure it out... you will want to focus on the oil pressure at the high-pressure sensor on the oil filter flange, the sensor there, or the wiring to it.

As per my instructions above, I'd start by getting a mechanical gauge hooked up to see what your oil pressure really is.

Vince
...
written by Talon, April 07, 2010
I have 1.8 Golf and the Oil light comes on and the buzzer sounds at low RPM (engine warmed up)and they go out if I rev up the engine? No lights or buzzer while cold. It would seem to be a low pressure situation but with the high pressure warning?
...
written by Ian, April 01, 2010
You have helped me with the timing a year or so. Now I have a 90 diseal Jetta with no tack. I have a crashed car with a instrument pannel with one. Is it a easy thing to change the insterment pannel and hook up the tack and all the different gauges. Is the wiring harnes in the car with out the tack got the wirering in it? I have the generator from the crashed car and all the parts. If you could help It would be greatly appreacieted . Ian
...
written by Erik, February 07, 2010
Ive had similar experiences and know several ways to get rid of that pesky buzzer, in a safe reliable fashion. first thing ive noticed is through all of my vw's, over the years the oil screen in the oil pan (one the bottom of the oil pump, clearly visible after it drips in your eye) that gets blocked up. take down the pump by three easy screws, buy replacement seal or wing it, and remove lower pump tube. its got two screws. use a can of brake cleaner and clean inside and out,scrubbing with an old toothbrush. the crap gets lodged inside the tube and you cant see very well from outside so dont be satisfied with a cursory inspection. at 180k (miles) i replaced my oil pump just because while these engines do last, a srop in oil pressure over time is expected and any losses are much more critical to an older engine. other problems include restrictions in oil travel, for which i only recommend BG products oil flush (in the red can). works a champ. i flushed my motor before cleaning the screen last, and replaced the pan gasket. problem solved.
on another note if you have a loose connention to your oil pressure senders this will also trigger the warning buzzer but is rarely the cause. take care to unscrew them and spray clean the hole in the end, to allow proper readings. thank you!
...
written by Ant Harvey, January 20, 2010
Hi - great article. I think I know, from what I've read, what my problem is but I want to double check. My 1.8 8v Mk2 GTI runs great, no smoke, no knocks, even idle, no overheating etc. When it warms up (oil at 90 deg and water at first marker - as high as it goes) the oil light flashes at idle, anything over 1000rpm and its off. It either flashes regularly or today flashed very quickly and intermittently, just stopping for a split second and rapidly flashing again. From cold it come on as you turn the ignition then straight off. Can you give me your opinion? many thanks, Ant
...
written by Rick, December 30, 2009
I was able to change out the intermediate shaft bearings in my MKII Jetta by removing the front and rear motor mounts and tilting the belt-side of engine downwards. I then removed the intermediate shaft through the passenger side wheel well.
...
written by Hennie Stander, December 05, 2009
Hey man,good article!
Quick question..
I removed my mk2 1.8l 8v head recently because a water port corroded and caused the head gasket to fail. Had the head welded and skimmed and installed it again. Car runs nicely,engine sounds good,but since i installed the head,i'm suddenly getting the oil buzzer problem when i've driven the car hard for about 30miles,rev it,and it goes away.. I'm using the same 20w50 oil i've always used.. is there anything in the head that can cause the car to have low oil pressure since the repair?
Thanks

Hi Hennie... thanks for your comments.

That's a strange one for sure. Since it's the buzzer and it's going away when you rev it has something to do with the hi pressure sensor circuit/sensor on the oil filter flange.

I can't actually think of anything you could do to the head that would cause low oil pressure directly at the flange. As per my writeup I'd recommend getting a pressure gauge in there to see what's really going on... could simply be a sensor that decided to crap out at the same time as your repairs.

thanks again for your comments,

Vince
...
written by Ambet P, July 07, 2009
WHOOOHAAAAAAAA!!! thanks for this... really a big help!!! smilies/smiley.gif
...
written by Josh, May 01, 2009
In diesel quantums, the engine need not be removed to replace the intermediate shaft bearings. With the radiator out, the condenser rotated up and out of the way, the grill off, and the front engine support removed, you can jack the front of the engine up enough so that the center line of the intermediate shaft can be accessed via a slot in the front end. Via this slot, you can extend a threaded rod, and utilize the procedure for installing and removing both intermediate shaft bearings utilizing home made or custom crafted(recommended if you don't have a lathe)tooling as described in the "show us your custom tools" sticky thread over at the vwdieselparts.com/forum site.




Hey Josh... thanks for the useful suggestion... I've updated the HOW-TO to reflect your additional information.

Vince
...
written by Cale, April 12, 2009
Great article, friend. Thanks for helping us keep our cars in good shape. Long live the Mk2.

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