New Valve Cover - Leaking oil Cap

[Novice]

Here's what I got...

I picked up a new VC from a junkyard, Mine was ugly. I found this one on the ground so it was pretty dirty. It had some dirt and sand on the inside of the cover as well. I took it to a car wash and sprayed it with de-greaser and cleaned it up. Also took some q-tips and cleaned it all out.

It had a pcv valve on it. I could only blow air through one way so I left it on. I put on the new VC and now under boost my oil cap is leaking. It never leaked on the old VC. I had also installed a fuel filter in-line as a catch from the valve cover to the intake.

I removed the fuel filter catch and hooked up direct back to the intake and the cap still leaks under boost. So at this point I'm worried I have excessive pressure under my Valve Cover. Like it's not venting properly. Or maybe coincidentally , my oil cap goes bad after swapping Valve Covers?

Wondering if anyone has ran into something like this before...

[ROOKIE1]

You know it is the cap how ??? PCV is cheap , should replace it .

[Novice]

Is leaking oil cap symptom of a bad PCV?

I think I might have the one from the old Valve Cover still. I guess I could try that one. Or maybe the old one is bad because it wasn't keeping pressure that it should so the oil cap wasn't leaking?

Heh, kinda going in circles here.

[snowborder714]

Get a new o-ring/gasket for the oil cap.

Part number - MD311638

[No_Skillz]

You should do a BLT and check for crankcase pressurization. However, if your dipstick isn't blowing out at boost, it's probably negligible. But the BLT should be done regardless.

Then, you have the option of bending the tabs on your oilcap a bit to make a tighter seal, getting a new rubber gasket (can be had by just buying another oilcap from Autozone - take off the new gasket and put it on your old cap, including the old gasket), or sanding down and polishing the lip of the valve cover to ensure a flat sealing surface.

Or all of the above.

[Novice]

The dipstick does come out under boost, before the new Valve cover. But that thing looks pretty old so I have some wire holding it now.

At this point I am going to put the old pcv back on and see if that helps. I'll keep you guys posted.

Unfortunately at this moment I don't have everything I need to do a Boost Leak Test.

My main concern in not the leaking oil cap but that it's leaking oil with the new VC and not the old one.

[LASER4G63T]

I had a problem with my oil cap coming loose/leaking and the PCV checked out.

I bought three new oil caps from auto zone because they kept coming loose. I finally broke down and bought one from the dealer and it is 10000000000087664 times better. Definitely worth the 20 bucks.

If you decide to get a new oil cap don't bother getting one from auto zone, orielly's, or advanced. They all have the same manufacturer and I have had zero luck with them. Get the Mitsubishi part.

[Novice]

Update,

Put the old pcv valve back on and it' still leaking under boost. So, I guess coincidentally my oil cap gasket went out when I changed my Valve Cover.

Thanks for all the responses.