996 Oil Pressure - 3.6L

I've been looking at a variety of posts where oil pressure has been mentioned and some of the info seems really inconsistent with what I see on my own car. Generally warm-up just peaks over 4 Normal cruising varies but rarely goes over 4 Highway and higher RPMs between 3 and 4 Idle fluctuates and sometimes seems to bounce around between 1-3 Interested in what others experience and if these seems really off. The car is pretty new to me so I'm always looking at this and wondering if its within reason.

These seem like subjective measurements on the gauge - as in what does a 4 translate to? Is the measurement scale accurate? How does it map to actual PSI values? I agree and would like clarity on this info as well.

It�s reading bar (pretty close to atmospheres - 100kPa while 1atm is 101325Pa). Each tick is 1bar = 14.5psi.

Yeah, can't imagine Porsche would have put a pressure gauge in the car and not made it measure a somewhat standard range for the same engine. What I'm interested in understanding is what is normal. I know my temp sits at 180 constantly once warmed up - assume all of the 3.6L 996 engines are similar. I'm assuming the oil pressure has a similar normal range under various temps/loads. Otherwise they wouldn't have put a gauge in.

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When I first bought the car the pressure gauge will hit about 4.7 when starting cold. it gradually comes down and settle right at 1 when car is fully warmed at idle. it generally it goes up and down with the rev. I.E 2000 rev, its a little above 2, 3000 rev a little above 3. However the needle will jump every so often, i mean it will go up and down half a bar for a second randomly. When I was at the track it never deep below 1 but stay right at the 1 line, on the last session of the day at a DE, i got the low oil pressure message on the dash. Checked and I didn't lose a drop of oil. With key in on but engine off, the needle will settle at random place between 1 and 3. Replaced the oil pressure sensor and here is how it behaves now: 5 when starting cold. it gradually comes down and settle right at 1.5 when the car is fully warmed at idle. When I was in traffic jam I think it went further down to 1.2/1.3 but never get to the 1 line. The pressure goes up and down with the rev still and its still at 2.3 when 2k rev and so on so forth. With key on but engine off, the needle does not move up.

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Just want to comment that this is THE strongest indication that the sensor is bad.

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You were experiencing oil starvation most likely. This is a common occurrence when tracking the M96 motor. There are some bandaids that can help with this problem that have been posted on the board including deeper sumps, extended pickup tubes, baffles, etc.

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Yes! I only did this 1 day and looked into the issue. Changed out the oil pressure sensor and looked into the deep sumps and such... but I decided that I won't be tracking my car... just going to stick with street and do what I can to make it last on the street.

The manual isn't much help on the subject but here is the reference: For me its very similar behaviour - 5 when cold then fluctuating depending on throttle when hot.

Oil pressure is usually pegged from 4-5 at idle and running when cold. It should only drop when warm, and it will drop to as low as 1 bar at idle. However, even running hot, the oil pressure should go up with RPM. The old rule of thumb for most engines is 10psi or better per 1,000 RPMs. Note that 1 bar is 14.5psi, so most 996 engines exceed the rule, including the minimum 3.5 bar (51psi) at 5,000 RPM. Anything above that is good. Mine is usually pegged at 5 bar when hot at anything above 2500-3000 RPM, which is quite a lot of pressure if you think about it, although appropriate for the 7,300RPM redline.

Not trying to highjack this thread, but I trying to learn signs of oil starvation before it becomes too big an issue. I've had multiple porches on track but I'm putting my 996 on Sebring for the first time this weekend. New R888r Tires will help the car sustain close to 1.2g+. I have the stock oil pain, not a baffled oil pan or the X51 pan. If I begin to strain the system and pull oil away from the pickup, will there be small warning signs I can look for?

Oil pressure drops to zero, warning light comes on, and blam! At racing RPM's, in a turn your focus is on your exit point and not on the gauges, so in a split second, no oil to crankshaft, spin a rod bearing and throw a rod through the crankcase. If you're going to track your car, proper equipment and preparation is an absolute necessity. Even then...well...have fun at the track with your "porch". Prime example https://rennlist.com/forums/996-foru...-on-track.html

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Yeah, I wouldnt do this.

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Oil pressure below 3bar while the engine is over 5k rpms during hard, sustained cornering is an example.

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Good read + insight. Anything can happen I'll keep an eye out for this. Conservative RPM in turn 1 through bishops will help

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The oil pressure gauge (sensor) fitted to the engine may not be that precise/accurate of a sensor. There can be some dampening of the pressure displayed, almost certainly there is, as I recall when I had a direct reading (a small diameter nylon tube ran between the engine block oil pressure port and the gauge) oil pressure gauge in one of my cars, my first car a Datsun 510, the oil pressure needle twitched like crazy. It is not easy to fit a high quality gauge to the car so one can monitor oil pressure while driving. In the shop the tech could fit a test gauge -- probably 'T' off where the factory sensor is located -- and with the engine warmed up observe hot idle oil pressure and then bring RPMs up to say 5K and note oil pressure at this engine speed. The factory manual probably has a call out on oil pressure but I don't what off hand this is. (For my 996 Turbo it is "Oil pressure at n=5000 rpm, T = 90C: Approx. 6.5 bar".) (I seem to recall -- but don't quote me -- the factory manual for the 996 NA engine has a slightly lower oil pressure under similar conditions specified.) In some way you could then "calibrate" (at least in your head) the car's oil pressure reading with the test gauge. (I did this with the coolant gauge of both my cars. I observed the OBD2 coolant temperature vs. needle position over time and thought I had it all worked out. But after a while I just said to heck with it. I don't need to know the exact coolant temperature only that the engine is cold, warm/hot, or too hot and the temperature gauge is plenty good enough for that.) Based on what you posted the numbers are in the ballpark. BTW, my Turbo's oil gauge needle bounces around a bit sometimes when the engine is up to temperature and idling. Been doing this for as long as I can remember ever since I bought the used in 2009. There is probably a marginal connection or the sender or sensor is flaky (?) but the sender is hard to get to and I haven't bothered to replace this. If it were easier to get to I might try a disconnect then a connect to see if this improves the sensor's behavior. (Surface corrosion can develop that can interfere with the voltage signal sent to the DME and if this is the case a disconnect/reconnect can be the cure.)

My gauge is pretty stable, more so that your one and others I have driven are also stable. It sounds like you may have intermittent oil flow (partial blockage) or a faulty gauge.

I just replaced the oil sender unit on my 2002 911 4S a few months ago and the oil pressure seems a bit erratic. My 996 used to start at 4.5 bars, then consistently go down to 3.5 when warm and stay there. Now it starts at 5, eventually starts going down to 3.5 when warm, then goes down between 1 and 2 when in neutral. When I step on the pedal, it goes back up to 4.5 - 5. Is that normal? If not, any ideas (e.g. replace Sender Unit again in case new one is faulty)?

That sounds about normal to me based on what my 996.2 does. Pegged about 4.5ish til warm then hovers around 3 for awhile, then finally 1.5ish when idling. Once the cars fully warmed up pressure rises with throttle input. Mine had a new sender installed about 2 years ago because I never quite hit 5. Still doesn�t quite reach 5. 🤷‍♂️

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Yes, it is working normal now (was not before)..

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Agree

+996 on working correctly The biggest change I noticed with the new one is stability. The old sender would read correctly but it moved erratically - the new one is more stable