Oil pressure problem

The car is a 1987 16 valve Scirocco.

When the engine gets up to operating temperature, and it's run between 2200 and 2800 RPM the oil pressure warning activates. Get it above 2800, it shuts up. If it falls below 2800, it activates again. Gun it, to get it above 2800, then shift so it's running below 2200, it stays off. Bring it up to 2200, and it activates again.

Any ideas?

- Bill _________________ I want to stand in the dark and see an audience feel the way I do.

Reply to
Bill Leary
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I had a similar problem in my old '87 Golf. I figured it was either a flaky sender or low oil pressure. The oil pump was replaced when I did my engine rebuild at 360K, the engine at the time had 630K so the pump had nearly 300K on it.

I followed the Bentley manual for testing the two oil pressure switches. That seemed to indicate both were working properly. At this point I assumed that the oil pump was weak and not providing proper pressure. I decided to test actual oil pressure, just to be sure. I bought a cheap oil pressure gauge & sender at a local parts store. I pulled the stock high pressure switch (there is a low and high pressure switch) and grounded the wire to ensure the oil pressure buzzer wouldn't trigger. The high pressure switch is normally open. Pressure closes the switch - thus you have to ground the wire to stop the buzzer from triggering. Installed the pressure sender for the gauge, ran the wire out the back of the hood and through the window and taped the gauge to the dash. For power I used an old cigarette lighter plug and taped 12v & ground from that. Went for a test drive. That verified that my oil pressure was low. Spec is 30psi at 2000rpm on a warm engine. Don't remember what mine was but it under 30. Replaced the oil pump. Used the gauge to verify I was getting higher pressure than before. Re-installed the stock sender and never heard the buzzer again.

First step is to follow the Bentley manual testing procedure for the switches. If you don't have a Bentley, I can send the info to you.

Todd Seattle,WA '86 GTI, Red of course. (exciting racey car) 273,000 miles '01 Golf TDI, silver. (new work car) 290,000 miles '87 Golf, Polar Silver. (retired work car) 654,000 miles

Reply to
racertod

I've got the Bentley. I didn't find that section when I looked for it a while ago, but did just now. Thanks.

- Bill

"Bill Leary" wrote:

I had a similar problem in my old '87 Golf. I figured it was either a flaky sender or low oil pressure. The oil pump was replaced when I did my engine rebuild at 360K, the engine at the time had 630K so the pump had nearly 300K on it.

I followed the Bentley manual for testing the two oil pressure switches. That seemed to indicate both were working properly. At this point I assumed that the oil pump was weak and not providing proper pressure.

I decided to test actual oil pressure, just to be sure. I bought a cheap oil pressure gauge & sender at a local parts store. I pulled the stock high pressure switch (there is a low and high pressure switch) and grounded the wire to ensure the oil pressure buzzer wouldn't trigger. The high pressure switch is normally open. Pressure closes the switch - thus you have to ground the wire to stop the buzzer from triggering. Installed the pressure sender for the gauge, ran the wire out the back of the hood and through the window and taped the gauge to the dash. For power I used an old cigarette lighter plug and taped 12v & ground from that. Went for a test drive. That verified that my oil pressure was low. Spec is 30psi at 2000rpm on a warm engine. Don't remember what mine was but it under 30. Replaced the oil pump. Used the gauge to verify I was getting higher pressure than before. Re-installed the stock sender and never heard the buzzer again.

First step is to follow the Bentley manual testing procedure for the switches. If you don't have a Bentley, I can send the info to you.

Todd Seattle,WA '86 GTI, Red of course. (exciting racey car) 273,000 miles '01 Golf TDI, silver. (new work car) 290,000 miles '87 Golf, Polar Silver. (retired work car) 654,000 miles

Reply to
Bill Leary

Betting you've got 2 oil pressure switches, one for high speed and the other for low speed. What you're hearing is the low speed oil pressure buzzer.

In my 89 Golf, I had to run 20-w50 dino oil in there to keep it turned off. In the winter, I ran Syn oil 'cause it started easier. There are also after-market high volume oil pumps -- I know that Parts Place in Auburn Hills MI sold a boatload of them.

Tim Wohlford '89 Golf (sold after 250k miles) '98 Jetta (182k miles)

Reply to
geek49203

Yes.

Yeah, I'm running 20w-50 right now. It cranks harder when it's cold, of course, but I haven't had enough trouble to cause me to switch to something lighter for winter. Of course, now that I think about it, I try to avoid driving it during the winter anyway so maybe that's why I don't have trouble.

I'm pretty sure from what I've been hearing that my oil pump is on the way out. I'll test the pressure sensors before I have it replaced, of course, but it seems likely.

Thanks for the comments.

- Bill

Reply to
Bill Leary

If the OP is low, you should be able to hear the bigend bearings hammering.= It wont necessarily be that loud, but present all the same. You warm the engine, then using a jerky motion, gun the throttle so it goes= to about 2500 rpm. If they are crook, you'll hear a soft "brapatatatat" no= ise.

As to how this is happening? Its likely due to advanced wear of the BE shel= ls and or the crank-journal is worn out of spec. There are other possibilit= ies, like blocked oil-galleries due sludge, stuck pressure-relief valve, to= o thin an oil. Engines that have advanced wear *should not* be run with syn= thetic oil,..use mineral 20w-50 or 20w-60. Oil pump wear is not a common ca= use. But oil-pump pick-up gauze blocked due sludge, and a lackof oil-tight = mounting of pump,..ie>>drilling may have the mounting bolts bottoming in th= eir threaded holes [had a Valiant doing this]. Some3 times other bearings l= ike the cam and or auxilary shaft bearings can rob the rest of the bearings= of presure. Toss a new filter in her, in case its faulty...

Jason

Reply to
5sfe22l

I'm haven't noticing that, but now that you've described it, I'll check it out.

I'm running 20w50. I usually do in water cooled VW's. I've never been quite convinced about synthetic oils and have been a bit leery about using them in an engine that's been run on traditional oil for a long time and lots of miles.

I did do an oil and filter change, which didn't seem to help or hurt the problem.

I managed to get a VW factory original oil pump. The guy who got it for me said there were only two of them left in stock in the US. When I take it apart to do the oil filter, I'll investigate the sludge issue.

Thanks.

- Bill

Reply to
Bill Leary

I'm haven't noticing that, but now that you've described it, I'll check it out.

I'm running 20w50. I usually do in water cooled VW's. I've never been quite convinced about synthetic oils and have been a bit leery about using them in an engine that's been run on traditional oil for a long time and lots of miles.

I did do an oil and filter change, which didn't seem to help or hurt the problem.

I managed to get a VW factory original oil pump. The guy who got it for me said there were only two of them left in stock in the US. When I take it apart to do the oil filter, I'll investigate the sludge issue.

Thanks.

- Bill

Reply to
Bill Leary

and a lackof oil-tight mounting of pump,..ie>>drilling may have the mounting bolts bottoming in their

threaded holes [had a Valiant doing this]. Some3 times other bearings like the cam and or auxilary

shaft bearings can rob the rest of the bearings of presure. Toss a new filter in her, in case its faulty...

Try some 15W-40 diesel oil, such as Rotella and see if that helps before going to something thicker.

Reply to
PeterD

If you are running 20W-50 now have you tried 15W-40 yet? It may be that the 20W-50 is too thick to flow well in the passages. (OK, that's remote, but possible...)

Reply to
PeterD

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