pl

2.5 bar when idling? what kind of oil do u use?

pl

no, your manual won't tell u about idling oil pressure.

QueenCityCarrera4

I had the whole car gone over after I picked it up in St. Louis, this included an oil change with the "water" oil. I have done nothing since. I watched it again this AM, as soon as I start it up, it goes to 4.5+ and stays there whether I am driving or idling. Sounds like others have it the same, but for me, it has NEVER registered this way.

It never made it to full temp before I hit the gym. After leaving, get back in car and it tops out at 3.5 at idle???? Its acting normal after everything gets warmed up, but the 4.5+ is not what I have been experiencing. Could the start of colder weather in the past couple of days cause this? Cincinnati AM temps have been low 50's? Just want to make sure I am not driving and causing an issue! Thanks

rcg412

Queens city - it sounds like your car isnt fully warmed up, so your 3.5 at idle on a cold car sounds right. Remember as oil warms it becomes less viscous (and there are 9.25 qts of oil in the m96 engine).

I posted a similair question a few weeks ago, I was getting ~3.5 >4K RPM, and 1-1.25 bar at idle. While not uncommon, the answer seems to be from the weight of the oil... 0w40 just seems to get to thin for these engines. I am running 15w50 now, and I get 1.5 when car is HOT at idle, and >4 bar when >~4K RPM.

I have a feeling that you are going to see dealers go back to 15w50, the original factory fill...0w40w is too thin for these engines.

1999Porsche911

Check your oil level. Low oil will cause low pressure and and overfill will cause high pressure. Your pressure should be as I stated earlier. A warm engine is one that has been driven for more than 20 minutes. What year car do you have, anyway? If you are not above 4 bar in pressure when driving a warm engine, you may either be low on oil or it may even be a bad oil sending unit.

QueenCityCarrera4

Whats actually happening now, as opposed to all of the other days in the first 4 months, is that it is 4.5+ at speed AND idle. It has never done that, it would at least drop down a bit at idle. It now stays at 4.5+. It does go to 1.5 at idle like it used to when warm.

I did check my oil level and its right on the money. The car is a 2001. It is going to 3.5 + at 4k RPM or cruising speed, so all is still good there. I am thinking since the "problem" just started and the weather just started to turn, that that is the cause. Its just that I have never seen it go to 4.5+ at startup and stay there whether cruising or idling until warm. I just dont want to screw the darn thing up. Could it be the gauge is starting to go bad???

1999Porsche911

Regardless of the ambient temperature, once the engine is warmed up, the pressure guidlines I stated earlier still apply. If you are getting a change in reading, I would first look at the oil sending unit. You may have a bad ground or need a new unit. They do go bad at times and it is not a big deal to replace. Not having pressure above 4 bar when cruising above 3000 rpm is unlikely mechanically, so sending unit or gauge would be my guess.

rcg412

agreed - sounds like something silly.... not engine related. my 0.02

Tippy

mine in south texas on a 100+ degree day gets as low as 0.8 bar at idle with 15W-50 weight mobil one

1999Porsche911

That's because your engine is running extremely hot. In 100F+ temps, without modding the radiator fans to keep the coolant below 200F, your engine temps is exceeding 220F while driving below 60 mph. Do the fan mod and you can drive all day long with engine temps below 200F.

In tests that I have conducted in 103F temps using 15W50, I was unable to get the oil pressure below 1.3 bar (using a calibrated, inline pressure gauge). This was even letting the engine temp get to 230F and idle of 800. Removing 1 quart of oil from the engine made the pressure drop by .3 bar in same conditions. Those with idle below 800 will experience slighty less pressure.

QueenCityCarrera4

to all for the info!!!

Chris996

Wanted to know if you fixed the problem? I have a 2000 996 with the same problem.

bgiere

Thicker oil will indeed give you a higher oil pressure reading but the normalized flow (hot) should not change, just the pressure that is generated from pumping it! Motor protection is dependant on the volume of oil pumped to the surfaces which are cooled and lubricated by that volume, not pressure...if you feel better seeing a higher oil pressure on your gauge, thats OK, just be aware that pressure is no indictation of an oil doing any better at protecting things. Lubrication protection is determined by volume, not pressure.

Chris996

I switched to moble (water) 0w-40 with same high oil preasure readings. I don't want to create a RMS problems.

2fas4u

That's exactly what my mech. says with the miles I have I need oil flow not pressure and he recommended 5w30 and I never have a problem. fwiw he's owned and worked or these cars since 74.