P 964 C2 low oil pressure when hot
Discussion
I have just test driven a p964 C2 with 111000 miles on the clock.
Oil pressure was aroudn 1.5 bar idling at traffic ligths whilst warming up.
then dropped off to 0.5 bar.
Oil level was low so added 1 litre of oil.
as car got hotter at idle warning light would come on and go off again once motor was revved above 2500rpm.
when driving oil pressure around 4.5-5 bar.
is this terminal or what do we check?
Oil pressure was aroudn 1.5 bar idling at traffic ligths whilst warming up.
then dropped off to 0.5 bar.
Oil level was low so added 1 litre of oil.
as car got hotter at idle warning light would come on and go off again once motor was revved above 2500rpm.
when driving oil pressure around 4.5-5 bar.
is this terminal or what do we check?
Oil pressure at running speed should be 4-5 bar, over 3000 mine sits at 5.
At tickover I think cold mini is about 2.5 ish and hot maybe 1.5-2? I'll check later, mileage shouldn't make a difference to oil pressure as the bottom ends are very tough, however if the oils been low who knows.
At tickover I think cold mini is about 2.5 ish and hot maybe 1.5-2? I'll check later, mileage shouldn't make a difference to oil pressure as the bottom ends are very tough, however if the oils been low who knows.
All sounds a bit iffy - 0.5 bar at idle seems low. I never see the temp go above the second white mark either (9 o'clock), even on track. As the oil plays a part in the cooling, could be that the oil pump is not very efficient especially at low engine speeds - don't know how to confirm this, but it's an engine out and split the case job to replace it.
When the engine is warmed up at idle guage should read about 2 bar when on the move at steady revs it should be 4-5 bar. You say you put some oil in are you sure you put enough in. Is the oil level gauge behaving properly i.e.moving up as the pressure gauge moves down. These cars do go through a lot of oil even if they are leak free.
If all the above are checking out and functioning properly then I'm afraid its something serious and will probally require an expensive garage visit.
If all the above are checking out and functioning properly then I'm afraid its something serious and will probally require an expensive garage visit.
Sorry to state the obvious but did you check the oil as per the handbook? I.e. fully warmed up, on a level surface and with the engine running?
Also, the handbook suggests using 1 litre of oil per 1000km is normal, although this may ralate to a brand new car as I have never experienced one that uses quite so much.
A friend has a 3.2 that was reading warm (2nd white mark on gauge) after a full comprehensive re-build but it was the gauge or sender that was faulty, the actual engine temp was fine.
As Mike (Sports & Classic) says, don't assume the info on the gauges is correct. Have a specialist connect another gauge that will tell the true story and see how that compares to your dash.
Also, the handbook suggests using 1 litre of oil per 1000km is normal, although this may ralate to a brand new car as I have never experienced one that uses quite so much.
A friend has a 3.2 that was reading warm (2nd white mark on gauge) after a full comprehensive re-build but it was the gauge or sender that was faulty, the actual engine temp was fine.
As Mike (Sports & Classic) says, don't assume the info on the gauges is correct. Have a specialist connect another gauge that will tell the true story and see how that compares to your dash.
I have a 125,000 mile C4 and, on the very odd occasions where the oil temperature DOES get up the the 10 o'clock mark, it's not uncommon for the oil pressure to drop to alarming levels. I have to say, though, that it's VERY rare for oil temp to get to that state - maybe sitting in a traffic jam for 20 - 30 minutes might do it. I find that keeping the tickover up to around 1000 rpm with the throttle is enough to keep the oil pressure at reasonable levels (i.e. 1 bar). At speed the oil pressure is usually 4.5 to 5 bar as others have said.
BTW, with a dry sump engine as in the 964 the oil level is somewhat divorced from the oil pressure. As long as there is sufficient oil in the tank to prevent the oil pump sucking air it will have no effect on the oil pressure. The pressure is created by the pump - not the gravitational effect of the tank contents.
Dave
BTW, with a dry sump engine as in the 964 the oil level is somewhat divorced from the oil pressure. As long as there is sufficient oil in the tank to prevent the oil pump sucking air it will have no effect on the oil pressure. The pressure is created by the pump - not the gravitational effect of the tank contents.
Dave
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