Oil Cap Air Sucking Noise

[Burg Boxster]

Cap should be firmly tightened.

Get the CEL code read (AutoZone and most places like will pull it for free w/ their OBDII). Most likely it'll be code P1128.

Sounds like you might have a bad cap again. More than likely though it's a cracked oil filler tube which is spreading open when you firmly tighten the cap... It is DIY-able w/ plenty of instructions here. Search on oil filler tube if that is indeed the case.

Start w/ getting the CEL code read first. Post it here for further diagnosis.

Good luck

[root_werks]

I agree, there are a few common codes for oil fill tube etc. Grab the code(s) and post them here.