I did a quick search and didnt see any comments on this.

I did a boost leak check this weekend. Found my oil cap started to leak when the system pressure was around 18-20psi. Anything higher then that then it was really leaking.

Anybody ever encountered this?

What I did to fix it: I took the original rubber seal out and placed 3 different sized or ings in there. The o rings all fit inside each other. Thats not a very clear way of explaining the o- rings but imagine one o ring then another one slightly smaller that fits inside, then another inside that one. Then I put the OEM rubber seal back on and no more leaking.

I also shot my dip stick out at only 25psi. Never had this happen. It came out like a rocket and its a good thing i was on the other side listening to the UICP or else I wouldnt have much of a face any more kinda dangerous. Be careful! I always thought the possibility of a pressurized hose bursting while your listening close to it but i dunno...

 

That's crazy, never heard anything like that before but 25psi is a lot of pressure. Good thing you were not near the dipstick! Good luck.

 

maybe pcv or valve seals....GL

 

Yeah I wasnt aware that there should be any pressure in the valve cover. But I do know that previous times that i would do a boost leak check I would get some slight pressure in the tube thats going from the valve cover to the intake tube. You wouldnt hear air rushing from it. But If you plugged it up with your thumb it would build some pressure slowly. Then when you would remove your thumb it would release that pressure.

The car has 63k on it. But Iv always maintained it pretty well. I also more recently but GSC s2 cams and beehive valve springs in, form what I remember since actually had the head off for the install the valve seals felt nice and tight.

 

you were probably performing the boost leak test wrong. Did you vent off your pcv valve that normally goes to the intake pipe or did you cap it?

Also as others stated, it could be you PCV(by the intake manifold) is stuck open...therefore the air from the intake manifold is going right into the valve cover.

 

if you have a hose running from the intake pipe to the valve cover I usually put a vice grip on it during pressure testing. There's no need to pressurize the valve cover

 

I do have a hose running from my valve cover to my intake pipe. Im pressurizing at the turbo inlet so the intake tube is off of course. I did plug this tub off with a bolt so there was no leakage.

From what I understand the pcv valve is on the back left hand of the valve cover if your facing the engine from the turbo side. The hose that comes form that valve does not run to my intake pipe. The hose that comes from the front (closest to you) right of the valve cover does run to my intake pipe, as I stated just above it is capped off.

sooo im confused as to what your saying?

 

nope, you've got it right, I assumed you were putting air in after the mas with the stock pipe

 

So maybe should the valve cover not be pressurized in this case? Maybe Ill just pick up a pcv and swap it out just to eliminate a problem... Shouldn't be too expensive.

 

do not cap off the pcv/breather from the valve cover to mas pipe...this needs to be left open to vent...

Heres my pic for reference during a recent boost leak test.




As you can see i connected 4-5ft hose this gets fed into the driverside interior. This is so that the light hissing sound didn't throw off the hunt for leaks.

 

Ok so this means that there is supposed to be some pressure in the valve cover? And if I don't cap this hose off like you have it shown above then the system will of course not hold pressure. If its leaking out of that hose then its obviously not a closed system.

So this is ok? I can pressurize with constant feed of pressure and listen for leaks using a air compressor. But Ive always read that you should be able to charge the system with 20psi or so and have it hold that for a while. Like 10 min. I could never get it to do this of course. lol

Also someone above commented on 25psi being a lot of pressure? The factory boost was 21psi and im touching 23psi once in a while normally. How is 25 a lot? Id say 35 is a lot.

I recently had somebody tell me that I needed to charge the system to at least 45 psi to be sure there are not leaks? That didn't sound like a good idea to me. More of a safety hazard with turning rubber couplers into grenades.

 

I run 45psi on the turbo but only pressure test to about 15psi for what it's worth.

 

yea i would replace the PCV first then go from there. shouldnt be expensive at all, and easy to replace.

 

There will be pressure in the valve cover during boost leak tests,this is almost inevitable. The hose I have is not plugged it's open. If you read what I said in my prior post and look at the picture, it should make sense. The valve cover is not supposed to have too much pressure, it really can't handle it. So during the boost leaks you're supposed to allow that built up pressure to escape.
I attach a long hose and route it to the inside of the car so that the "hiss" sound does not distract me.

30psi is what I run through my system during boost leak tests. The air slowly bleeds off over a few minutes till it settles @ 0 psi.

You can also remove the pcv valve and pressure test it yourself for peace of mind. You can see if it's stuck open from sludge from blow by/crank case oil(insert image of oil catch can...they actually work)

 

you guys may have solved my idle problems! i noticed a black residue around my PCV valve and oil cap. my cars idle jumps like crazy and stall sometimes when i push the clutch in..especially going in reverse...