Oil pressure

[snarf]

Questions on oil pressure have cropped up on a number of occasions and generally the answer is high is good, my MY07 normally runs at 5 bar at circa 3000 rpm, However, the erratic behaviour noted at idle does sound strange so it might be as well to get the sensor checked out.

 

[porcar]

I would appreciate any feedback on oil pressure readings for a first generation 3.8 litre 997. I have recently upgraded from a 996 and over the weekend noticed some erratic behaviour from the oil pressure guage. I checked the manual which indicates that the pressure should be 3.5 bar at 5000 rpm whereas mine under fairly restrained driving was quickly stuck to the max of 5 bar at anything close to 3000 rpm. Everything else looked perfectly normal - oil temperature at 90 - 100 and coolant a steady 80. The oil level is fine and the car hasn't consumed any oil over the thousand miles since I have had it. I also noticed that on a couple of occassions when the engine came to idle after a medium to long run that the guage jumped to the maximum 5 bar rather than settleing down to the 1.5 - 2 bar that you would expect. It stayed there for a short while but did then drop. This all seemed a little strange but as I haven't had the car long it is difficult to judge. I have read through a few earlier posts and did note JFK made reference to a guage that had moments of madness that was cured by the fitment of a new oil pressure sensor and wonder if anyone else has had any similar experience. My car is a 2006 model Carrera S which has done 29,000 miles. Any thoughts would be most welcome.

Thanks, Paul.

 

[okellyt]

Like Allan, once running mine usually sits up at 5,only really dropping down to 3.5 at idel at a lights or similar. It does vary a bit with revs and throttle applied. Am now paranoid as after reading your earlier post I was out and noticed my oil pressure varying at idle, but this mirrored the revs and I realised I was ever so slightly brushing the throttle (see above) So 5 on oil is good. Variation - need to keep an eye on it - if with engine revs not necessarily a problem but if it starts going a bit mad - Probably time for some one to look at it.

 

[porcar]

Thanks for both of the replies and it seems that my high reading when on the move is in line with both of your cars so nothing to worry about. It does beg the question though as to why the manual should suggest that the reading at 5000 rpm should be 3.5 bar. I will keep an eye on the erratic behaviour of the guage at idle speeds and agree if this persists it is one for the mechanics to look at. I suspect that it could be a faulty sensor as found by JFK in his thread. I will post news of how this goes in due course. Cheers, Paul.

 

[garyw]

To add that mine is also usually on 5bar on anything above tickover... garyw

 

[snarf]

ORIGINAL: porcar . . . It does beg the question though as to why the manual should suggest that the reading at 5000 rpm should be 3.5 bar. Paul.

I think below average numbers may be quoted to fend off warranty claims; another example is the specified maximum oil consumption limit of one litre per 1000km.

 

[JFK]

Mine did the same - it developed a mind of its own reading various different pressures when hot at the same engine speed, including indicating 5 bar at idle. JZM diagnosed the oil pressure sender unit (a reasonably inexpensive fix) and once replaced all was well. JFK

 

[porcar]

Thanks everyone you have put my mind at rest. I shall now look forward to enjoying an early morning jaunt down the A3 tomorrow. Have a great weekend, Paul.

 

[tscaptain]

What is a good oil pressure reading in the Gen 2 is a mystery! Like the Gen 1 the manual gives the 3.5 bar at 5000rpm figure but with the on demand electrickery oil pump the pressure fluctuates all over the place depending on revs, engine load and engine temp. The only obvious sign that it is doing the right thing is if you're cruising along at, say, 2000rpm and give it a lot more loud pedal then the oil pressure increases significantly faster than the revs rise. I'd be interested to hear the other Gen 2 owners observations on oil pressure.