a lot of pressure build up in valve cover area?

[96CosmosM398TI]

i have been experiencing a annoying leak coming from my oil cap i have tried multiple caps that were good and nothing. i bent the flaps on one today and installed it, drove home 2 miles. popped to hood to see if it helped and still leaking a bit. i decided to take off the cap and when i did the thing almost went flying off from the pressure build up. is this normal? i have never seen this?

[CirrusSR22]

Pressure in there should be relieved by the crankscase vent valve. I guess it's possible the CCVV has failed/blocked. I've heard stories of the valve cover vent hose, which leads to the CCVV, being blocked with crud as well. Mine has already disintegrated from what I assume is exposure to so much oil.

[96CosmosM398TI]

i just replaced mine with a brand new oem one..... but that does make sense because it was around that time when it started happening thanks a lot

[CirrusSR22]

Hmmm.... The flange in-between the intake manifolds (where the CCVV bolts to) has some small passages. I guess it's possible there's a blockage there. ?? Just throwing out ideas :)

[cooljess76]

3 things will cause excessive pressure in the valve cover. 1 being a blocked passage going to the CCV line on the actual valve cover and 2 being the ccv valve itself being bad. You could take the CCV valve apart but 9 out of 10 times it will break on you, so have a new one handy and ready to install when you take it apart. It probably needs to be replaced anyway. And the 3rd reason for pressure buildup would be bad piston rings. I read somewhere that leaking rings will allow carbon and crud to build up on them and cause a dangerously high pressure condition. This could be checked by doing a compression check. You shouldn't have more than 200psi in each cyl. I think ideal is around 190psi + or - 5psi. First I'd replace the CCV and check the passage going to the hose at the valve cover. Good luck.