Oil pressure guage drops nearly to zero a few minutes after startup. I have not noticed any adverse effects yet (and dont want to). The pressure increases when the throttle is pressed but will sometimes not rise at all. Could theoil pump be going out?

 

It's most likely just the sending unit, at least lets hope it is. I would start there before assuming the worst. If you had 0 oil pressure all the time, you would have noticed by now! Replace sending unit and let us know what happens.

 

The Sending Unit Is almost always suspect will unusual Oil Pressure fluctuations. Atleast thats what I always found and experienced myself...

 

I doubt its the sending unit and more than likely stuck thermo valves in the oil cooler and E shaft.

 

I had this same problem, and it turned out to be the sending unit!!!

 

if it was stuck thermo valves, wouldn't it make the oil pressure be high at idle since it's basically not allowing for flow and then jump even higher as the load increases?

Tim

 

Yes. You could relate the same analogy to that of the Thermowax found behind the TB which effects Idle but In this case, effects Oil flow.

However, the Thermo Valves, found at the Oil Cooler, could be partially seized or limted In range of motion. i.e going halfway up or down etc.

I'd still consider replacing the Sender Unit first.

 

Actually no. When either gets stuck (there are two, one in the oil cooler and one in the E-shaft) the pressure drops to about 15lbs at idle and goes up to maybe 30 or 40 while running. The problem is that the valves bypasses the spots that normally keep the pressure up to help warm the engine.

The other oil leak issue seen more on S3 and S4 13Bs is the front cover, but typically the oil pressure will go down with increasing RPMs if that is a problem.

 

Don't bother trying to repair the notoriously failure-prone and inaccurate stock oil pressure gauge. Get an aftermarket one and then you can properly trouble-shoot the problem.

 

Like I did.