Boost pressure in valve cover ? - SRT Forums

bmpblue · 09-19-2009, 04:29 PM

While boost leak testing recently, I had pressure leaking out from under my valve cover, right behind the cam position sensor.

There are only two things I can think of that could cause this:

#1 - leaking check valve in PCV line to throttle body
#2 - leaking valve seals

Is there anything else I may be missing ?

randallsrt · 09-19-2009, 04:39 PM

get a better in-line check valve between throttle body and PCV valve..... oil build up may cause it to not function properly, do you have a catch can? and is the Check Valve between throttle body and catch can?

SilverBeast · 09-19-2009, 04:45 PM

The PCV is on the top of the valve cover by the passenger side. Take it out and re boost check it. Plugging that line that goes to it. This will tell you that it is leaking out the crappy PCV checkvalve. About $10 at the dealership for those and very easy to install.

If the problem persists I would get a leakdown test done to see if you have intake valves with worn out seats...

bmpblue · 09-20-2009, 01:20 PM

I should have explained better. I already have a good check valve in-line. Either the check valve is stuck open, or I have leaking valve seats. I was trying to find out if it could be ANY other thing causing this.

omnidog · 09-20-2009, 05:51 PM

does it do same if ya bump the motor over a lil bit? An intake valve is prob open in a cyl and goin around the rings. May wanna try a cylinder leakdown check

randallsrt · 09-20-2009, 11:12 PM

Take the vac line off the pcv valve while boost leak testing... That will tell you if the check valve is bad

bmpblue · 09-21-2009, 10:42 AM

OK ... Just capped off my PVC line and I'm still getting the leak out of my valve cover. This means my valve seals are leaking

raul-01 · 09-23-2009, 12:35 AM

No. Replace your valve cover gasket and remember to add a dab of RTV in the specific areas.

It will find a leak somehow. When you boost leak test your car your TB is closed, but it will find a way past it, and if it does it will pressureize your crankcase and put your seals and gaskets to the test. I wonder if a boost leak test can mess up your throttle plate? I mean when you are driving and going into boost that throttle plate is open.. Boost leak test, it is not and jamming up against it.

What do you mean you capped off your PCV line?

SilverBeast · 09-24-2009, 04:09 AM

Careful here.

When you say it is leaking out of your Valve cover do you mean where the gasket is or the hole on the driver side at the top of the valve cover. I think the post before me thinks its leaking out the gasket and I doubt that is what your talking about.

ptperformance · 10-03-2009, 06:20 PM

Yes, where is it leaking, because if your not getting any leaking past the PCV system then you might want to stop there and do a compression test.