High Pitched Noise when accelerating: 2015 S80

OldSchoolGuy · Post by **OldSchoolGuy** » 26 Jan 2024, 06:59

When I accelerate I hear a high pitched noise and read that it could be eliminated by removing (lifting) the oil dipstick. I did this and seemed to have worked but what it causing it as you should not have to do this??

dikidera · Post by **dikidera** » 27 Jan 2024, 00:58

PCV is due a change. If it's sucking in and you have trouble removing the oil filler cap then some diaphragm is worn and there is very high vacuum. If on the other hand it feels like it's blowing out then you have very high crankcase pressure.

Post by **Skymongrel** » 29 Jan 2024, 17:29

If it's like the 2007 S80 it's an easy job. The sucking in and out reference is in reference to a PCV (Positive Crankcase Ventilation) system test where you can put a rubber glove on the oil fill neck and if it fills with air then your not ventilating properly. I recall that mine failed this test and inflated. I went ahead and replaced the PCV component. Note that I didn't have the loud noise you are experiencing. But that is a classic sign of failure.