Former VWDieselParts.com Forum

In a previous post I wrote:

WOOO--HEW! Car is fixed! SAGA is ended.

My saga has not ended.
The oil pressure switch was wrong, and was causing my light to flash as soon as the engine reached 2000 rpms after it started flashing it would continue until car was restarted. THat problem is gone but...

Now once in a while, for just a little while, the light will start flashing then later it will stop. I've got some more info to share.

Note: I'm still needing a OPCU for a diesel car. I posted earlier that FineFrank was going to send me one but turns out he doesn't have one. If anyone has a diesel instrument cluster or speedo with a OPCU in it that they would want to sell PM me or post here.

Yesterday I was able to pinpoint the circumstances that my light starts flashing. (note: before replacing the switch it would flash immediatly after passing 2000 rpm's and continue to flash till the car was shut off.)

At steady accel at 2100-2200 rpm the light will start flashing. If I coast or stop and rev the engine above 2000 rpm the light stops flashing. Obviously a dynamic problem.

Next check will be moniter voltage on dynamic switch under the same circumstances that the light starts flahsing. Probably the switch is turning on the light and then later turning it off. If that is the case I'll test the oil pressure with a gauge under the same circumstances that the light starts flahsing. I checked pressure before but only at idle.

Long delay.

I realized I had a non-turbo switch in there. The non-turbo switch is 1.8 bar and the turbo switch is 1.4 bar.

My theory is the oil line to the turbo uses (looses) a little oil pressure so turbo takes a different switch.

With the new switch installed problem is 10X better but the light still comes on and flashes but just every once and awhile.

Swapping in a turbo switch may be a "quick fix" for someone with slightly low oil pressure in a NA motor.

I may try thicker oil and switch back to regular oil instead of using synthetic as I have been. Maybe that would be just enough to keep the light off.

First of all, thank you for all the good info. you have presented here as you have learned about the system. I had recently broken my speedo trying to fix the odometer on my '85 Jetta diesel, and replaced it with a gasser speedo from the same year (which I also had to fix.) I didn't think anything of the OPCU, and used the gasser but was getting the buzzer and light when the engine was hot. I figured it was a good opportunity to put good oil in it and went with the german Castrol 0-30 to improve mileage. Still buzzer and light at idle. When I found your thread about it, I went back and changed out to the diesel OPCU and that cured it! Comparing the OPCU's, the board looked exactly the same with the same number of components and most of the exact same components. I dont know much about electronics, but it seems that you could desolder the components that aren't exactly the same and swap them to your intact board and make your own diesel board. Just a thought.

First of all, thank you for all the good info. you have presented here as you have learned about the system.

Thanks! I really appreciate that. I wanted to contribute something to this forum and your feedback is appreciated. I believe these are great cars and with the sharing of information (and maybe parts) that the internet makes possible we can now keep these fine vehicles alive.

When I found your thread about it, I went back and changed out to the diesel OPCU and that cured it! .

Hey! Thank you. Maybe thats what will finally fix mine completely.

I dont know much about electronics, but it seems that you could desolder the components that aren't exactly the same and swap them to your intact board and make your own diesel board. Just a thought.

I might try that unless anyone can get me a OPCU? (classifieds here aint working so great)

Last resort maybe I should buy that dealer OPCU????? ARRRRGGGHH!

Sorry to resurrect this old thread but I got more info.

In this thread-----> <a href="viewtopic.php?t=6282&postdays=0&postorder=asc&start=0" target="_blank">No oil pressure</a> Homer T. Coyote had a Flashing oil pressure light and eventually fixed it by replacing his Intermediate shaft bearings shown in the following picture.

Homer T Coyote's worn out Intermediat shaft Bearings



So I get to thinking....

Maybe that is what has been causing my problem all this time(look at the date this thread was started but take into account that the problem was happening along time before I started the thread. I was convinced I didn't have a oil pressure problem and that it was just electrical because when I put a pressure gauge on the circuit it never went below 20psi which according to the spec I was using was ok. Well, once again I'm wrong.

IMHO your SAGA has just begun.

hagar.

Your right hagar. (see below)

Previous Intermediate Shaft Bearing pic is Homer T Coyote's and the below pic is mine. (mines even worse)



Sorry about duplicate content from <a href="viewtopic.php?t=6550" target="_blank">Engine Pull Thread </a> but I think that these replacing these bearing might bring my Oil Pressure Saga to an end but............................................................ the story continues on the <a href="viewtopic.php?t=6550" target="_blank">Engine Pull Thread </a>

Good picture CoolAir. IMHO this is must check item w/ the VW diesels. Those bearings look defective to me. A bad bond w/ the materials. VW would have went bankrupt if they had to issue a recall.

Sort of. The bearings in CoolAir's car lasted 160,000 miles before the odo broke and an unknown number of miles afterwards. It is true that they are one of the weak links in the VW diesel engine, but can more miles than that actually be expected? I would also say that they are always worn on the side the T-belt applies pressure to. I am quite sure that in almost all cases it is a case of the timing belt being installed too tight and applying too much pressure to the bearings. The same is true for the injection pump shaft bushings.

Andrew

Once again sorry to resurrect an old thread but I have since rebuilt the motor using new Intermediate shaft bearings, thrust, rod & main bearings, pistons and 36 mm pump.

I've now put on enough miles that I think I can verify NO MORE FLASHING OIL PRESSURE LIGHT! Note: I still have the Gas OPCU in the car and I've driven about 30 miles or so.

Saga ended.


Among all the other problems I think intermediate shaft bearings was the final fix. The larger pump certainly didn't hurt but probably wasn't necessary.

Hey Andrew why didn't you tell me about the Int Shaft Bearings when I first opened this thread????

(because I put a guage on it and said oil pressure was ok??)