Oil Pressure

[Guest]

Hi I'm new to the forum (and to Porsches !)

I am slightly concerned about the Oil Pressure guage which in normal driving never seems to dip below 5. The on-screen oil guage on my car reads full i.e. all three 0.4 litre segments are lit.

Is this normal ? Does the small upper segment light up if the car is over-filled ?

Thanks, Akis

 

[snarf]

Akis, the oil pressure gauge reading will vary with engine speed and oil temperature and should not be affected by oil level, providing of course it is not so low as to starve the pump. When warm mine runs at around 5 if the revs are 3000+

The level gauge will indicate an overfill, I had this reading once with the car parked on an incline.

 

[Guest]

Thanks.

 

[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.

 

[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.

 

[snarf]

I reported a similar problem in an earlier post.

OPC; reluctant to take my word that there was an intermittent problem, suggested leaving the car with them so they could verify the fault. As this might have taken several months I naturally declined this offer.

The next time the oil temperature was 90+ and the oil pressure reading was stuck on 5 with the engine on tick-over I took a photograph of the instrument readings. As a result the OPC agreed to investigate and subsequently changed the oil pressure sender.

Problem solved

(Just remembered I need to add this to Gary's warranty post)

 

[adrian996]

Hi Stuart. I've read your post a few times now and I can tell you that there's absolutely nothing wrong with your car.

The oil pressure on the 996/997 engine should read 5 bar at start up when cold.

This is partially due to the increased viscosity of the oil when it's cold. As the engine warms up the oil pressure should drop and settle around 2.5 to 3 bar at tick over. If you rev the car at this point you will notice that the oil pressure rises and falls again - just the same as your tachometer (revometer) - you're increasing the oil pressure when you rev the car and decreasing it when the engine settles back to tick over again.

It's always a good idea to use the oil pressure gauge as a sure indication of knowing that your engine is up to working temperature before you put the engine under any pressure (revving it above 2,000 - 2,500 when cold for example). When the oil pressure is settled at around 2.5 bar at tick over you know that you can then let the fun begin without damaging your engine. This is a better indicator than just using your water temp gauge.

I would imagine that any dodgy car mechanics would gladly take your money to investigate this 'problem'.

It would take a very long time to cure though!![]

Adrian.

 

[snarf]

Adrian - you're right I jumped to the conclusion that Stuart was experiencing the same problem as I did.

 

[stuey]

Cheers Guys, thanks for your input.

One thing though Adrian this has never happened before. Today though the needle was stuck at 5 for around 15 miles even at low revs (1500 - 2000rpm). It only started to fall when I was just a short distance from work and even then it fell down to 1.5. By this time the engine was & had been fully up to temp for a while. When I parked up it then started to behave normally - I kept blipping the revs and it rose up & down as normal.

Normally for my car from cold it does not go straight to 5 & stick there, it is usually around 4.5 - 4 and depending how I drive usually rises and falls. I try never to boot it until all indications show engine is fully up to temperature, so that is why I found it strange to be stuck at 5 this morning. It did have an oil change last month, but it has never behaved like this before & had car 14 months.


Will keep a close eye on it & let you know any further developments - thanks again.
Stu

 

[adrian996]

No problem.

I might be wrong but I would guess that you may have been running very slightly low on oil for a while prior to your oil change and, now that it has been replenished, you are only now noticing that she's running at what you think is higher than normal(?).

But be assured that it isn't. The oil pressure needle should be wedged right up against the limiter until she's warm.

Adrian.

 

[garyw]

Mine sits bang against the top of the gauge when its cold or at revs.. only time it drops is to about 2.5 on tickover and hot.
All other times its reading a happy 5 []

I think Adrian has pointed out what it could have been...

garyw

 

[stuey]

Cheers all for your input. Panic over as they say.

[][][][]

Stu

 

[JAH]

Now I'm panicking!!

I've got a one year old gen2 997 c2s. On start I get an oil pressure of 2.5 to 3. When I accelerate it goes to 4 or a bit higher and then returns to 2 to 2.5 when cruising. Been like this since I bought it - also a mate with a gen2 997 says his readings are the same as mine.

Do the gen2 engines behave differently??

Jonathan.

 

[adrian996]

It's quite possible that the Gen 2 engine behaves differently to the 997 & 996 - but I'm not sure, sorry. It's a DFI engine so it is quite a different set up to the indirect injection.