Oil cluster light and buzzer

Hi all, I have an 83 Mk1 GTI, 1.8dx. I know this has been done to death, I've read every post I can find but here I am…

The car has been off the road for 4+yrs and when last driven the dash oil pressure light was flickering with the buzzer intermittently coming on under all driving conditions. I only ran it a mile or so to get it home like this. 

Now I'm trying to get it back on the road and am stumped, done a full service inc new battery, filters etc and changed the high and low pressure sensors. On start up the light flickered brightly, the engine sounds good no unusual noises. I checked grounds, I put in an additional clock ground from pin 2. After that the buzzer has started coming on without starting the engine. I've checked power to the sensors, I get 10.5v to the high sensor before starting the engine and nothing to low, that doesn't seem correct, no?

I'm thinking of testing the oil pressure, need to buy a test kit, and if ok deleting the cluster system and running a gauge. Id rather not do this as I'd rather fix the issue. 

Any help much appreciated!!!!!!

The oil pressure dynamic warning system or buzzer is a "L" shaped PCB that is located in your Speedo.

The Buzzer is because there is Low oil pressure at High RPM.

Now your sense wire on the oil filter flange (white) sender could be grounding out as it may have a nick in it, but it is Best to test the Oil Pressure.

The Sender on the side of the head is low oil pressure at Idle.

What weight of Oil are you usnig and are you using a
Mann, Mahl, Genuine VW, STP, Mobil 1 or Wix Filter, as the Filter and the wieght of Oil that you are using can cause issues as well. Don't use FRAM, Bosch or Generic Filters

Buy or Rent a Mechanical gauge, and know what your pressure is.  Don't guess.

Rapid response, cheers!!!

It's a UFI filter, I have a Genuine VW filter I can put on if that's no good and the oil is Millers 10w40, is that too light? 

I would suggest that you find out what your oil pump is doing, as sitting that long your oil pressure by-pass could be gummed open.

Never heard of a UFI filter but it is a UK company.
When you check your oil pressure refer to the Bentley for your Model engine and year.

In my Cabby  Minimum oil pressure in Cabriolets is 2 bar at 2000 rpm with the oil temperature at 80°C.

When I had a wire jump off of my 90 whilst I was tooling down the road at 85 mph… The Blinking Light abd buzzer forced me to stop by the side of the road, and pop the hood.  Connector flipped off, tightened it with pliers and no worries the rest of the 800 mile trip and 1000 miles back.  But I knew I had good working pressures prior to leaving the City.

On my 92, and 93 Cabbies both Auto's I had great pressure on both but opted to change the oil pump over to the 2.0L one taller gears.  I still had good pressures.
But as I live in the deep south where the summer road temps are easily 140 degrees F.  I want the increased output.  I eventually installed external oil coolers and those were solid running cooled engines.

But I too had the electric Oil pressure gauge in the car, and checked it against a mechanical gauge before and after the swap.

Knowing the Pressure when your buzzer and light are warning you is a better thing.

As Briano1234 says, check your oil pressure with a proper guage just to make sure that you have oil pressure.

As to the buzzer, there is a single transistor on the oil pressure warning board (the "L" shaped board that is in behind the speedo). If this fails, the buzzer will always sound. Took me some trial and error to work this out, but replacing the transistor worked for me. I managed to  get one the same spec (based on the number on the transistor) but the pin-out was reveresed so I fitted it, put the lot back together and discovered nothgin worked so I had to take it all apart again to rotate the transistor, loosely fitted it, checked it, all good, then put it all back in properly.

For good measure I run a seperate oil pressure guage, but I went for mechanical one, so I have a capiliary line running up in to the guage. A lot of folk think this a bad idea in case it leaks, but it was good enough on older cars, and provided you do it up properly, it's not going to leak!

paceman said

As Briano1234 says, check your oil pressure with a proper guage just to make sure that you have oil pressure.



For good measure I run a seperate oil pressure guage, but I went for mechanical one, so I have a capiliary line running up in to the guage. A lot of folk think this a bad idea in case it leaks, but it was good enough on older cars, and provided you do it up properly, it's not going to leak!

If it was good enough for a jag, Austin Heally Frog EYE, my Mg Midget, and Rover 3500S its good enough for your VW.  Gotta Love Mechanical Gauges.

On a side note.
The Viscosity of your Oils is also a possible issue that a Lighter weight oil when hot will thin.  

For Sake of argument I used to run 10W40 in all my British cars no issue,  I ran 10W30CC/CD in my Diesel rabbit, and then 20W50 in my later rides as in Toyota's and Cabriolets.  when I started to drive This Century cars the Specs on those changes to 5W30 Synth.

On my Cabriolets and 20W50  I would get here in Georgia USA down in the teens in the winter, and well over 100 in the summers, and I had no flashy blinking or buzzing from Oil pressure issues.  I did howver use High Quality Filters as in the nes mentioned above, Wix, Genuine VW, Mahn, Mahl, Mobile1, and Pureolator Gold.

I did have issues with Generic store brand, FRAM, and Bosch.  That went away after I replaced the filters with good ones.  It appears that the Anti-drain back vale wasn't on Fram, or Bosch, as well as most Generics.

Thanks all for comments. As suggested I've now checked the pressure from the oil filter housing with the engine warm, not sure exact temp but the cluster gauge temp was mid point.

Idle - 1bar
2000rpm - 2.4bar

Should I test pressure from the side of the head also?
For info the engine was fully rebuilt 7yrs ago, new everything and I've covered a pitiful 1k miles before laying up 4ish yrs ago. 

Is this pointing to an electrical issue do you think?

As for the oil, not sure why I went with 10/40 given Haynes suggests 15/50 or 20/50. Think I'll change the oil grade and the filter to the bag one I have. Other than that I'm stumped, I'm not great with electrical issues unless basic. Defo gonna fit a separate pressure gauge, had one in minis with plenty of success.

I'd check at the side of the head, I think that is where the buzzer circuit gets it's signal from.

Since your pressure tests are good,  that is if the oil was up to temp of 80C then I would first change the white Low pressure at High RPM sensor that is on the oil filter flange.  Second suspect is the Wire from that cable is broken in the sheath, so I would test it for resistance between the End of the wire on the sensor to the wire feeding your clocks.

I don't have a 83 wiring diagram, for the GTI but I should be the same color that is on the wire end of the sender.

Cheers Brian's will do, it's painfully slow progress with this ad I only get a few hrs a week on the car, till Friday it is.