Cayenne 06 VR6 – Oil Pressure Low Warning! – Love the car! Please HELP

[955Rich]

My wife’s Cayenne got the “Oil Pressure Low Warning!”  I read many posts and many tried to change the oil pressure sensor which I did.  Unfortunately, I swapped out the sensors.  A couple of days later, “Oil Pressure Low Warning!”. 

I purchase an oil pressure gauge and unscrewed the oil pressure sensor and replaced with the gauge to monitor the pressure.  These were my results:

1.       At idle (cold) started at 4.5 bars

2.       At idle (90C) was 1.5 bars which per the manual is at spec. 

3.       Revved the engine to 2500-3000, it was at 3.5 to 4.5 bars

4.       At idle (93C) was 1.0 bar??

5.       Revved the engine to 4000, it was at 5.5 bars

6.       At idle (94C) was 1.0 bar??

The manual and forums I read stated it should be 1.5 bars at full operating temperature.   

I love the car and always do all the required maintenance.  I change the oil every 3,000 miles with full synthetic. 

My question: is 1.0 bar causing the “Oil Pressure Low Warning!”.  I did not hear knocking during the revs.  The engine felt strong.  Could it be just a weak oil pump or something else?

Any thoughts or advice would be helpful!

[Loren]

 

I would not rev the engine to 400 rpm if I had a low oil pressure reading - 2000 rpm should be sufficient. If you did hear knocking it it would be too late for the engine.

This could be predictable if have low oil level or thin oil at high ambient temps.

 

1. Have you checked the oil level?

2. What weight oil are you using and what is the air temperature?

[955Rich]

I have not heard knocking.  Engine runs fine.  The first time it happened two weeks ago.  I stopped driving thinking it could be a faulty oil pressure sensor.  I changed it out within two days the warning came back.  I then proceed to install an oil pressure gauge in the oil sensor port.  I carefully let the car warm up to 90C.  The manual had a spec which was 1.5 bars at 90C.  It got exactly there and match the posts I have read from other owners.  Then tested from 2-3K and finally up to 4k and the results where noted above.  Once the engine temp got 94C he bar dropped to 1.0 which i think is low?  No knocking.

 

Every time the warning came on.  I shut the car off checked the oil level which is fine.  

 

I have always used 5W30 full synthetic for the past 3 1/2 years without any warning light.  The manual calls for 5W30.  I am considering using 0W40 which is slightly thicker and may not thin out as much.   I plan on doing the same testing to see if the pressure improves at the 90-94C engine temp and the light goes away.   

[Loren]

I think if you have air temps in the 90 degrees F I think 0W-40 would be better.

Also, you may lose some oil pressure as parts on the engine wear - so if you are at or near 100,000 miles I would consider that drop normal and likely anotherr good reason for 0W-40.

[955Rich]

Thanks.  My concern is engine wear or weak pump.   I have had cars in the 300k+ and never had an issue of using a thicker oil for the summer periods.  I do understand that the Porsche oil pump pressure is different from the domestics (GM and Ford).  I am not sure if this is typical for Porsche or VW  that as the car ages you would have to switch to a thicker summer oil?

[Loren]

Any car is going to have wear. The distances between parts increases with wear and that includes the oil pump.

Your readings are not that far off - so I would just change the oil and see if it helps.

[955Rich]

I plan on changing the oil this Thursday.  I still have the manual oil pressure gauge attached to the oil pressure port so I going to re-run the same test with the new oil.  Just curious to see the pressure.  I will post the results.  

[955Rich]

Here are my results with 0W40.  I am hoping the light does not come back onAt idle (35C) started at 4.3 bars

 

1.       At idle (41C) started at 4.0 bars

2.       At idle (46C) started at 3.5 bars

3.       At idle (52C) started at 3.0 bars

4.       At idle (59C) started at 2.5 bars

5.       At idle (68C) started at 2.0 bars

6.       At 2240 RPM (80C) > 5.0 bars

7.       At 2400 RPM (86C) > 4.8 bars

8.       At idle (90C) was 1.6 bars

9.       At 4040 RPM (86C) > 5.5 bars

10.   At idle (93C) was 1.2 bars

11.   At idle (94C) was 1.2 bars

 

If there are any Porsche techs, do these numbers look normal?

So far no warning.  The Cayenne runs great.

I am going to update if I see the sensor come back on or in a month.

[Loren]

Those numbers look good.

[955Rich]

UPDATE: After 3,000 miles the issue went away. I switched from 5W30 to 0W40. Hopefully, the data and results can help someone else!

Thank to all!