If pressure is confirmed low, then forget about the cluster. It is not an indication issue. Got to get to the bottom of whatever mechanical issue is causing the low oil pressure.

 

compression and blow-by have no relation to oil pressure, try running a Xw50 oil and see what results... have you replaced the small o-ring on the oil filter cap/cover?

 

It just had a major service and the workshop (Porsche specialist) spent hours trying to diagnose the oil pressure issue. I would assume it's been checked / replaced but I suppose it's not too difficult for me to check.

Any recommendations for oil to use?

 

Make sure it gets replaced and not just inspected. Worth buying a new one regardless.
I run Castrol, but Mobil is on the approved list...any name brand 5w50 is likely ideal. Could consider 10w60 too.

 

Pull the fuel pump fuse and crank the engine over with the starter. What oil pressure are you indicating? What gauge or oil pressure sending unit and method did you use to confirm oil pressure is truly low? We have deleted the factory sender instead using a highly accurate mil spec sending unit off of the filter housing. Good luck with getting it sorted.

 

30k sounds high for a rebuild. Maybe if you are upgrading some components or something or you have a bunch of parts torn up.

 

My auto tech buddies advised me the best place to check oil pressure with an accurate gage is at the factory oil pressure fitting.

The times I did this I'd get a suitable T-fitting with the proper threads (could be pipe threads).

You can take the factory pressure sensor fitting with you to correctly match threads of the factory sensor and thus to where the sensor connects to the engine.

Once I had a suitable T-fitting installed I connected the factory sensor to one leg of the T and then my pressure gage to the other leg of the T..

Once you have a suitable gage connected you take pressure readings. For the 996 Turbo the oil pressure call out is:

Oil pressure at n=5000 rpm, T=90°C: Approx. 6.5 bar

What pressure you measure depends upon what you do next.

 

My shop did a fair bit of testing including using a seperate oil pressure gauge directly on the engine. It confirmed my oil pressure was low once it heated up.

I’m planning to run a 5W-50 oil to see if that makes much of an improvement.
I suppose I have to consider a rebuild in the near future.

 

True low oil pressure won't be helped by running 5w-50 oil.

The "heavier" 5w-50 oil offers better high temperature high sheer protection but won't affect oil pressure to any measureable degree.

My experience with my 2003 Turbo is after running 0w-40 oil since I bought the car used in 2009 with just 10K miles to several years ago then switching to 5w-50 oil -- because where I live and drive while it doesn't get very cold -- 32F or lower is a rarity -- it does get darn hot -- 100F+ and it can hit these high temps in June or Sept. or anywhere in between -- I can't tell which oil is in the engine by the oil pressure gage and its behavior.

Low oil pressure can arise from a worn out oil pump -- excessive clearance at the ends of the pump gears which is an internal oil pressure leak -- a bad/stuck open oil pressure relief valve -- an internal oil leak -- oil from a high pressure oil passage is leaking out into the engine through a failed seal or sealing surface -- or the valve that controls oil spray to the pistons has stuck open vs. shutting off at lower oil pressure -- or excessive bearing clearance. In the latter case an oil analysis might turn up scary amounts of bearing metal in the oil.

My advice is to skip the 5w-50 oil and get the cause of the low oil pressure identifed and addressed. The risk is the problem may be relatively inexpensive to address now but if you continue to drive the car the low oil pressure could lead to excessive/accelerated wear to the point it "takes out" the engine via catastrophic failure of say a rod or main bearing spinning and breaking the rod or the crankshaft or shredding some bearings and polluting the engine with metal debris that renders the engine a poor rebuild candidate.

 

Offering my experience in case it helps. I had a low oil pressure issue that was driving me crazy, no one could figure out what was causing it. My mechanic was wracking his brain and eventually found out that a small chuck of a turbo had broken off and lodged itself in an oil line, causing the low oil pressure. Upgraded to k16 billets, replaced said oil line and all good.

 

Ding!!! Winner! You need bigger turbos!

 

Well my oil pressure problem is now solved.

I replaced the oil pressure sender and my voltage regulator.

Oil pressure gauge now sits at 1.6 bar at idle (hot) and 4.5 under throttle.

I’m so glad it was a cheap and easy fix and I didn’t have to spend $30k on an engine rebuild.

Thanks to everyone on here for your support and a big thanks to the guys who post instructions on how to work on these cars. Those instructions make it so much easier and they give you the confidence to work on our own cars.

 

Thanks for the update. Glad it proved to be just the sender and voltage regulator.

Have to mention the above doesn't jive with what you posted in an earlier post: "My shop did a fair bit of testing including using a seperate oil pressure gauge directly on the engine. It confirmed my oil pressure was low once it heated up."

Based on my interpretation that a voltage regulator "fixed" the oil pressure calls into question the correctness of the oil pressure testing using a separate oil pressure guage.

I have to stress it is very important the oil pressure be verified by a reliable oil pressure test. True low oil pressure is a rarity -- thank goodness -- but it must be properly checked and confirmed. What follows after true low oil pressure is confirmed differs considerably -- and by thousands of dollars -- from what follows if the oil pressure is found to be ok.

 

Yeah, i believe the shop lied to me about doing a manual oil pressure test.


They were really pushy in trying to get me to commit to an engine rebuild on the spot. They told me i shouldn't drive the car under any circumstances so i had it towed home to consider my options.


I'm so glad i did a lot of research and asked other Porsche shops. There is a small Porsche mechanic not far from me that builds all the Carrera cup race engines. He didn't believe the problem was internal and he said its just so rare for a street driven Mezger engine with low KMs to have an oil pressure issue.


Needless to say i won't be going back to that other shop ever again.