Oil pressure relief valve - OUCH!

p-talk · p-talk's Garage

Last weekend I drove the P car in the day for the first time in awhile ("100F is a cool day" mode here in AZ and AC doesn't work), and I has some oil pressure problems. Oil pressure was lower than normal, and once it was fully warmed up pressure went REAL low and brought the oil light on! I immediately drove it home and didn't let the RPM get so low as to let it get dangerous again, and I haven't driven it since.

I've been doing lots of research on the board here, and it seems that my OPRV may be the culprit. I figured no big deal, I'll just buy a new one for piece of mind, throw it in and be back on the road. But they're over $300 new!!! - CRAP!

So how do y'all feel about a good used OPRV? I've noticed some people have had good luck with this, or cleaning out their old one, but this kind of goes against my "fix it right and never worry again" philosophy. But then again, $300 for a little bypass valve also goes against my philosophy!

Eldorado · 06-22-2007, 11:25 AM

straight out of the porsche 944 manual...

"Engine oil pressure is shown in bars.
At 5.000 rpm, with the engine at normal operating temperature (approx. 90°C / 194°F), the pressure should be approx. 4 bar. A slight drop in oil pressure is normal under certain operating conditions such as prolonged highway driving in hot weather.
At idle speed, with the engine oil hot, the oil pressure can sink to 0.5 bar - this does not indicate any loss of engine performance.
However, if the oil pressure drops suddenly while you are driving, or if the warning light comes on, pull off the road, stop the engine and wait for it to cool down. Check the engine oil level. If the oil level is normal, contact the nearest dealer."

the manual also says that it's normal for the light to come on at idle, as long as it goes away on acceleration.

Icey1174 · 06-22-2007, 11:31 AM

Is the 944 and the 924 the same engine?

Eldorado · 06-22-2007, 01:01 PM

the 924S, yes it is

p-talk · p-talk's Garage

I usually contact you guys before my "dealer"

. .

Seriously, I'm seeing lots of other posts in the archives where people have much higher oil pressure at full operating temp at idle - mine does seem to sit at 0.5 bar once she's fully warmed up and the idle settles in this 100+ summer heat. The warning light did come on for just a second, during that "dip" period all 944 NA motors seem to have, but it's low enough that I'm not too comfortable - just want to be absolutely sure my motor's OK!

Quote:

Originally posted by Eldorado
straight out of the porsche 944 manual...

"Engine oil pressure is shown in bars.
At 5.000 rpm, with the engine at normal operating temperature (approx. 90°C / 194°F), the pressure should be approx. 4 bar. A slight drop in oil pressure is normal under certain operating conditions such as prolonged highway driving in hot weather.
At idle speed, with the engine oil hot, the oil pressure can sink to 0.5 bar - this does not indicate any loss of engine performance.
However, if the oil pressure drops suddenly while you are driving, or if the warning light comes on, pull off the road, stop the engine and wait for it to cool down. Check the engine oil level. If the oil level is normal, contact the nearest dealer."

the manual also says that it's normal for the light to come on at idle, as long as it goes away on acceleration.

fast924S · fast924S's Garage

Run thicker oil, I bet your running a oil thats too thin, run 15-50

p-talk · p-talk's Garage

What, no respect for the 924S, eh?! Mine weighs less, plus it's more sturdy and lighter w/out a sunroof, I'll take you on!

Quote:

Originally posted by Icey1174
Is the 944 and the 924 the same engine?

Icey1174 · 06-22-2007, 02:15 PM

Sorry!

p-talk · p-talk's Garage

I'm running 20w-50 with a quality filter, and the oil is pretty fresh.

Quote:

Originally posted by fast924S
Run thicker oil, I bet your running a oil thats too thin, run 15-50

944dan · 06-22-2007, 02:50 PM

Hows the idle speed, mine had a problem with that before it would drop real low when the engine temp got up there. i would run my idle at 5- 650 rpm's anything lower and your talking dangerous drop in oil pressure.....

Icey1174 · 06-22-2007, 02:59 PM

Is your oil pressure in your car any different than it was before? By the sounds of the manual and the extreem heat out there everything sounds ok. Sounds like a drop in the oil pressure while running the engine would be a concern and not droping below the .5 at idle.

p-talk · p-talk's Garage

It does seem like the oil pressure is behaving like before, just somewhat lower since the extreme temperatures. And the pressure did not drop or dip while driving or with RPMs above idle.

I'm thinking I'll take it out in the evening and see how it does, I hadn't had it out in the daytime for awhile (AC not working). I'll be out of town all weekend, but I'll have a little P-car diagnostic drive on the local 'twisty' to look forward to when I get back

.

And idle speed seems fine, it dips to around 650 or so then immediately returns to 850-ish. It's just that quick dip to 650 when the light turned on momentarily . .

Admittedly anal about his cars,

924S

Quote:

Originally posted by Icey1174
Is your oil pressure in your car any different than it was before? By the sounds of the manual and the extreem heat out there everything sounds ok. Sounds like a drop in the oil pressure while running the engine would be a concern and not droping below the .5 at idle.

Eldorado · 06-22-2007, 09:47 PM

Quote:

Originally posted by 924S
I usually contact you guys before my "dealer" . .

Seriously, I'm seeing lots of other posts in the archives where people have much higher oil pressure at full operating temp at idle - mine does seem to sit at 0.5 bar once she's fully warmed up and the idle settles in this 100+ summer heat. The warning light did come on for just a second, during that "dip" period all 944 NA motors seem to have, but it's low enough that I'm not too comfortable - just want to be absolutely sure my motor's OK!

mine runs *exactly* like this, for going on 5 years now (my ownership and the PO ownership)...

my starts out around 5bar at idle when cold, then as the car warms after driving, it'll go down to 0.5bar - 1bar at idle..

normal highway driving it'll land anywhere from 2.5bar to 3bar... that's around 2.5 - 3k rpm, give or take a bit....

I'm running 5w50 castrol synthetic. absolutely no change to when i ran 10w30 mobil 1.

pdx944 · 06-23-2007, 12:39 AM

mine never drops below 2bar.

p-talk · p-talk's Garage

Good to know! And you probably don't get really hot there in Canada - mine only started doing this once the 100+ daytime weather hit.

Thanks guys, I'll be looking over the car tomorrow night or so . .

Quote:

Originally posted by Eldorado
mine runs *exactly* like this, for going on 5 years now (my ownership and the PO ownership)...

my starts out around 5bar at idle when cold, then as the car warms after driving, it'll go down to 0.5bar - 1bar at idle..

normal highway driving it'll land anywhere from 2.5bar to 3bar... that's around 2.5 - 3k rpm, give or take a bit....

I'm running 5w50 castrol synthetic. absolutely no change to when i ran 10w30 mobil 1.