Internal engine pressure

[mcbutler]

Hi All,

23i 2009

I recently had my car to the local indy who told me that when they tried to remove the oil cap from the running engine it was difficult die to a negative pressure inside the crankcase.
They told me that the engine breather is integral to the cam cover.
As a result they changed the cam cover which was quite expensive.
The other day while cleaning the engine I decided to start it and see if it was still hard to remove, it did 'suck on' a little bit but nothing major.

My question is, should internal engine pressure be positive/negative or the same as atmosphere??

Seems to me slightly positive considering combustion leakage etc..

Any ideas chaps??

 

[GuidoK]

Should be negative due to PCV.

If you want to know if the valve cover was changed for a legit reason: now way of telling now; the part is gone for a proper diagnose.

 

[Mister T]

As above, slight negative pressure

 

[Smartbear]

Usually when the pcv is starting to go defective the car starts to burn more oil with sooty tailpipes etc, was your car exhibiting any of these symptoms? :?
Rob