Has anyone seen this 944 Turbo oil pressure situation before?

I noticed my oil pressure gauge needle was wavering up and down around the 2 bar mark when my car was at hot idle. The gauge’s needle was bouncing erratically every second or so, going as low as 1.5 bar and as high as 2.5 bar.

I became concerned about a possible engine lower-end bearing going bad. Here’s what has been checked and the result:

1. Re-seated and cleaned the oil pressure sending unit connectors. Problem persists.
2. Attached a MECHANICAL oil pressure gauge in line. Oil pressure variation/wavering confirmed – still there! So the factory oil pressure sending unit & gauge are okay.
3. Replaced oil relief valve with new OEM Porsche valve. Problem persists.
4. Drained oil and inspected oil pan with long gooseneck magnet probe. No sign of bearing failure/gray gunk/bearing shavings.

So I’m scratching my head now! Any advice on further items to check? A collapsing oil hose? Failed oil cooler housing gasket? What could it be???? I’d appreciate any ideas!

Thanks in Advance!
Andy

 

Andy, two things come to mind.
1. I'm assuming that this is a new occurance, and the guage did not exhibit this behavior before.
2. That said what work, if any, have you done recently.

The only thing it sounds as if you have not checked would be the crank pulley. Has it been removed recently? And if so, was it retorqued to 140 ft/lbs? And were the washers reinstalled correctly?

 

Hi ME944,

Crankshaft not removed or re-torqued anytime recently.

This is definitely a new occurance -- the gauge did not do this before.

No work done recently. Car is stock (not chipped, 115,000 miles). No knocking or other unusal sounds from engine bottom end.

Andy

 

I'd look for a cracked oil pickup tube. They tend to fail as they get older, since they are made of plastic they harden over time and are sensitive to vibrations, especially if you have bad motor mounts or a balance shaft belt that isn't in proper phase. The good news is that you can refreshen your rod bearings while you are in there, since you have to take the pan off to get to it...

Don't just go rushing off and do it on my advice, however... do a little research and make sure the symptoms match up.

Regards,

 

Scott, is that more of a problem with the turbo cars than the n/a's? I've seen and heard of quite a few people who resort to replacing the oil pickup tube, but it seems that I hear more from the turbos.

 

I'd never really thought about it before, but yeah, it is, from everything I recall about it. S2's and 968s seem to have the same problem, tho.

Regards,