911 sc oil light

[davidoft]

morning folks, just bringing my friends car out of its 10 plus year hibernation, got the brakes sorted, engine runs sweet after some tinkering, but the oil light comes on after it gets hot, oil pressure shows 1 bar a bit more perhaps at idle, goes up 1 bar per 1k rpm, tank oil level is at the top mark when hot, wiring looks ok, what am I missing

cheers

[jwhillracer]

Double check with a mechanical gauge, if it's OK, don't worry about it.

JW

[davidoft]

will do, its only when the temp is right up, whats the best grade of oil, hes change it but said it was correct

[jwhillracer]

I'm the wrong one to ask, still old skool enough to still be using HD30 …………..
What temp are you calling "right up"? 100 deg C?

JW

[911hillclimber]

Those pressure levels/rpm seem right to me and I use semisynthetic Shell oil, the engine, a stock 3.2, is about 140k miles old!
I think having the oil level to the max when hot is not a good idea, best to be between max and min to avoid engine smoke in my experienc, but I use the dip stick in the tank, not the gauge level in the dash.

[Strictly]

I personally run a 20w50 in a 911 engine with lowish oil pressure which is realistically coming apart in 10k to 20k miles, 15w 40 for the same with good oil pressure. I would use different oil (i.e semi or etc) in a rebuilt engine, but for one that is say good for 10 to 20k more a mineral is absolutely fine. At the end of the day a mineral was spec'd when they were new!

The oil spec is in the workshop manual, normally its set at something like X.X bar at XX00 rpm at 80 deg C

Its also in the owners manual (handbook) that it is perfectly fine for the oil pressure to come on at IDLE when the oil is at operating temperature (i.e 80 to 100 C).

[davidoft]

Seems he changed the oil to fully synthetic 5/30, it’s only got 60k on the clock so hopefully no need for a rebuild just yet, but I assume the oil spec to be the problem?

[Strictly]

Seems he changed the oil to fully synthetic 5/30, it’s only got 60k on the clock so hopefully no need for a rebuild just yet, but I assume the oil spec to be the problem?

Not necessarily, I have never tried a 5w30 in a 911 engine myself, im sure someone has and will chime in, but PROBABLY a tad thin!! In any case an oil change after running again after 10 years, is no bad thing!! I would look up the exact book spec on the oil pressure first, it is in the manuals, etc then decide.

[kitesurfer2]

I would never use fully synthetic in an SC.