Irratic Oil pressure reading and the cure !

[chrisg]

Dear All

Just thought I share with you my latest 'issue' with the 951. Ever since I've owned the car, the oil pressure has started from cold at a steady 4.5-5 bar dropping to ~ 2.5 when hot at idle. During last weekends visit to the ring, we started seeing some erratic readings = 3 bar at hot, and then widely swining needle at tick over even to the point where the red pressure warning light was coming on in the queue to get off the ring.

So, a bit of research on Clarks garage showed that the most likely culprit was the oil sender gauge. I was dreading the prospect of it being a genuine pressure issue....

I'm very pleased to report that it was the sender unit, a new unit fitted and the pressure readings are back where they should be, even with the oil temp up to 100C (albeit under high revs in the garage). Not the easiest of jobs to replace - had to pull off the PAS pump (to be replaced anyway) and the front ARB - easier with a proper 24mm open spanner than an adjustable.

BTW, Halfords have a cracking deal on their 20, 21, 22 and 24mm Professional Advanced box set = 4 spanners for £8 at the moment - well worth it for many 944 jobs (22mm = strut top and PAS banjo bolt).

Anyhow I'll report again once I've fitted the 2nd hand PAS pump to replace the one that failed spectacularly half way around the Nordschleife !

 

[Outrun944]

Interesting, I've been getting a similar thing lately.

9/10 it starts up at 4 bar, and drops to 2 bar on idle after a short run. This is normal behaviour of course.

After a while though, on a journey, increasingly I'm seeing it going down to 3 / 3.5 bar and sometimes as low as 1 when idle. Checking oil its on maximum and I can't find any current oil leaks - several were fixed recently.

Would you think this is the same sender unit issue? I have a standard 944 Lux (early '85) so perhaps isn't the same as the Turbo?

 

[chrisg]

Without refering to the PET it's difficult to say, however knowing Porsche I'd be very suprised if it was a different part - worth checking at www.dcautomotive.com ?

Yours

CHris

 

[edh]

Not as easy on a turbo, but you can remove the sender without taking anything off - get a 24mm open ended spanner & chop it in half. That way it doesn't hit the ARB. I seem to remember slackening off the PAS pump to get at it.