Personally i would not consider any mayo acceptable.
If i was buying a car with even a hint of mayo anywhere in the oil system i'd walk away.
If i noticed that on my car then i would change the oil straight away and monitor it after that.
The mayo is water mixing with the oil, so you have water getting into the system somewhere where it shouldn't be.
Even if it was a faulty PCV then the water is still coming from somewhere, as it certainly isn't coming from your intake system.
How do you use the car, is it used for lots of shorts runs or does it sit for long periods of time?
First thing i'd do is check the dip stick, if the oil is coming out as mayo on the dipstick then i would strongly advise not using the car until you've both changed the oil and rectified the fault.
How is the coolant level?
Have you noticed the car is putting out more smoke (from the exhaust)?
So you have this trouble also? As much as mine on the cap? I dont mind doing 5k changes that would be every 10-12 months anywayOil change every 5K too is what I do, I only do short runs also so it's my solution
I'm not loosing any coolant though? So the compression test won't show anything, or do you think it will for another reason?A compression test, to set your mind at rest.
Just noticed mayo under my oil cap for the first time, tiny bit on the end of the dipstick. My drive to work is only 6-7miles and car is only often used for short journeys, going to give it a blast out next week & an oil change...*fingers crossed*