I'm trying to make sense of “Oil pressure too low” warning.

On a 2006 Cayenne Turbo with ~200k miles. I get this warning only sometimes. Some day it drives for hours before appearing, and the next day is gone again. I scanned the car with an iCarsoft POR v3.0 > instrument cluster > oil pressure, and I noticed it gives the “oil pressure < min” when RPMs are below 1500 approximately, and “oil pressure OK” when above 1500. I really hope it’s the oil pressure sensor, I ordered one already.



No other symptoms, no rough running, nothing.
Any idea, suggestions, tips?

 

Need to check the sensor for sure but what brand & weight of oil are you using? Does this occur at idle all the time or only when the engine is hot?

 

Oil is Mobil 1 5w-40 with less than 5000 miles on it. I added ceratec and motor oil saver from liqui moly.

About the frequency I only just realized the RPM correlation so I just tested it once. But I got the warning a few times already. Sometimes staying longer (a good 30 min) sometimes goes away after a few seconds

 

As I said on FB, you need to check the oil pressure with a manual gauge. The procedure is in the shop
manual. You can also just swap the sensor and see if it goes away, but you won’t verify your oil pressure that way.

 

I will do it soon! I ordered the kit and will be delivered soon. But what if the values are actually low? What’s next?

 

From alldata: oil pressure may be low for a number of reasons. Oil is diluted, oil pump is faulty, bearing clearance too large, oil level is low, oil pressure regulating valve is faulty, or incorrect oil used.

I would start with with a fresh oil change and see if that helps. It might be a good idea, with your mileage, to try a 5W-50 oil for a pressure bump. If you try all the easy stuff, you may need a new oil pump…but let’s hope not!

 

What he said....Did it just start after the oil change occurred? If so I'd definitely do another one and check out the oil filter for sure, make sure it isn't restricting the flow. A 10w40 or as mentioned but harder to find 5w-50 may be in order, especially with summer coming up and depending on where you live. I hope you are not doing your oil changes at 10k+ as that is too long. Verifying the actual pressure is a must though before goiing down to many rabbit holes.

 

I've personally seen in my UOA analysis reports Mobil 1 shear to almost water in as few as 3,000 miles, so leads than 5,000 with that oil doesn't .ean it's still good.

For the best 5w50 oil you can run, try Driven FR50 since your Cayenne is not a DFI variant. I run this oil in both my 997s (one supercharged) and my GMC pickup. It may resolve you warm, low oil pressure issue without doing anything else.

At 200k miles though you may have bearing wear from using M1 that's contributing to the low oil pressure at idle.

 

I fully agree with Petza on the poor quality of Mobil 1 but I didn't want to open that can of worms. Even with poor Oil analysis date there will be a crowd that swears by Mobil 1 because they've made it to 100k with no problems. Same goes for those doing 10k oil changes, yes they may have made it but to 100k but probably not to 200k+ like most other quality synthetics will on shorter oil changes.

 

I got very similar problem. Mine is 08 V6. I changed my High Pressure fuel pump and it is good now.

 

The fuel pump on its way out is messing with the oil pressure? How does that work?

 

https://www.partsgeek.com/65lrjzg-po...e4ce09923dac0c

Like this one. On V6 engine. it is on the driver side close to the wall.

 

I think you're confused (or I am). How does the HPFP cause a low OIL pressure situation? Also, this is off topic, the OP has a 955 so no HPFP to worry about.

 

'06 is not a DI engine, HPFP running too rich/delivering too much fuel isn't an issue. 4.5's weren't D.I. not until the 4.8's did Cayennes get D.I. 200k is getting up there in mileage, could defintiley have a bit of bearing clearance depending on the Mx history/oil change intervals and oil quality.

 

+1
Occam's razor, simplest solution...
Classic symptoms of a worn out oil pump and mileage to corroborate.