FiatCoupe

I've noticed that in the summer in Houston with outside temperatures in the range of 95 to 104 my hot idle oil pressure is only 1 bar. I watched the pressure this morning and it was:

cold 5 bar
150 degrees 2.5 bar
175 degrees 1.75 bar
200 degrees 1.25 bar
225 degrees 1 bar

Normal oil temperature for me in this heat is at least 200 degrees and is usually 225 degrees. The water temperature gauge quickly reaches 175 degrees and stays there.

I'm using Mobil 0-40W oil. Is the engine showing signs of wear or should I be using a thicker oil, say a 50W, in these temperatures. At higher revs the oil pressure builds nicely. Car is a 2007 C4S with 50k miles on it.

I'm attending a DE day in a couple of weeks and I'm worried that the oil temperature is going to even hotter with a corresponding drop in pressure.

Thanks

John

Mike in CA

A more important check would be to see what the oil pressure is at higher engine speeds. The manual states that oil pressure should be at least 3.5 bar at 5000 rpm.

FiatCoupe

Thanks Mike, I'll check on my drive home.

Checked:

Getting 3.5 bar at 3500 rpm and over 5 bar at 5000 rpm so I'm happy.

okbarnett

If it drops to 1 at any point I would be worried. I would check everything , if all is good, then suspect a pressure sensor.

jhbrennan

I run 0W-40 in Austin (just as hot if not hotter than Houston) - daily interstate drive of 40 miles plus maybe 5 miles of street. Oil temp never above 205 and pressure at 5 bars at driving rpm. Idle maybe 1.5 to 2 bars. 25,000 miles.

Luxter

Here is your problem.

jhbrennan

Why is that his problem? He already responded he has no problem.

Luxter

A good quality A40 approved 5W-40 oil should give you a steady 2 bar pressure @ idle speed @ 200F.

McCulla

In Florida afternoon heat (high 90's recently), city "stop and go" for my drive home--no problem with keeping 2 bar at idle after fully warmed up (usually 225 degrees +). This is while using a "good quality" Mobil-1 0W-40. Is the message being posted we must use a 5W-40 to see those pressures being maintained?

Mike in CA

The rated high temperature viscosity is 40 for both Mobil 1 0W-40 and 5W-40. I don't see why the 5W-40 should maintain oil pressure at 200F any better than the 0W-40. Do you have any evidence that shows that Mobil 0W-40 is the "problem"?

JW911

This is exactly correct. They are both identical viscosity when hot. They are only different when cold. By definition, multi viscosity oils have two viscosity designations, the first cold, the second hot.

Luxter

Ever heard of engine oil shear out of grade? M1 in particular?
The evidence can be seen on my dash daily. Plus others on this forum who experience improved oil pressures, lower oil consumption and engines running smoother.
Just sharing my own experience.
I would be scared sh#%less if my oil pressure went down to 1 Bar like the OP.
Take it FWIW.

Mike in CA

I get it. So your issue is not with M1 0W-40 versus 5W-40. It's with M1 generally. Seems curious that Porsche would specify an inadequate oil. I've heard of anecdotal issues with M1 but no hard evidence. Would be interested in seeing some if it's available.

mike993c2s

I have just started following the 997 board recently. I knew that engine oil is treated almost like a religion among the air cooled crowd, but I didn't know it's also such a hot topic here (pun intended). I guess I'll get my popcorn out!

BTW, it just did oil changes for both 911's yesterday. M1 0W-40 for the new, and M1 V-Twin 20W-50 for the old (yeah, the thick, expensive stuff).

GMKatsiaris

Hey guys, new to the forum and it is very interesting to see how many problems can be solved through the forums
I am having the same problem with my 3.8 997mk1. I recently bought this car and the service now warning was displayed in the dash. I carried out the maintenance accordance to the mileage and year of the car and since then when the car is hot and at idle i get this warning "Engine oil pressure Low".
I am guessing that the previous owner went well over the service interval because the oil that came from the engine was tar like black.
I bought the car quite cheap and now i am beggining to understand the reason for the low price.
Any suggestions?
Checked the oil pressure regulator and it was fine, i replaced it though to eliminate this concern. I did another oil change thinking that sludge might be blocking something but the problem is still there.
Replaced the spring in the oil pump and still nothing.
The oil pressure drops to 0.8bar!!!!
Now desperation starts to kick in!!