q45 valve cover leak

[qship96]

if the gaskets fail,and oil seeps out-is there a chance that dirt will get sucked in and contaminate the oil?

[maxnix]

Not unless it is actually open to the outside. There should be a slight postive pressure, hence the seeping.

[elwesso]

Yep, and they will make your exhaust manifolds and surrounding area all dirty though.....

[Chally]

If your PCV system is working correctly, there will be a vacuum at idle & possibly at cruise.The oil will leak out any other time, especially overnight. Saying that, it would be unusual if it sucked in any dust.(PCV = Positive Crancase Ventilation)

[DAEDALUS]

The valve covers are vented to the intake hose before the TB. At idle and cruise isn't the air pressure before the TB the same as ambient?

[911/Q45]

I think there are also connections to the plenum, so the connection prior to the TB is probably an intake.

[DAEDALUS]

Exactly. There are 3 ports on each valve cover. 1 comes from the crankcase for blowby, 1 routes through the PCV back to the plenum, and 1 is a vent to the intake.

[Chally]

Sorry about the delay, but I'm not getting ANY emails letting me know the thread has been answered.

Regarding the venting, the vents before the TB are the breather pipes for the crankcase, but the PCV valve is after the TB & that is what creates the vacuum in the engine & scavenges the fumes from the engine. At idle, you should be able to take the Oil Cap off & a piece of paper or rag, should be drawn towards the hole, in fact, you should be able to feel the vacuum with your hand.Under hard acceleration or high revs, the PCV valve isn't good enough to take all the pressure in the sump etc so it can also utilise the breather pipes you mentioned earlier.

Hope this helps.

[qship96]

if i am understanding correctly,then the vacuum condition will cause air/dirt and dust to be sucked in through a leaking valve cover gasket?

[natsoundup]

don't mean to hijack the thread...but I have two valve cover gaskets to sell at a reasonable price.

[elwesso]

if i am understanding correctly,then the vacuum condition will cause air/dirt and dust to be sucked in through a leaking valve cover gasket?

THis is certailny the least of your problems..... You would have to have a pretty good leak for air to actually be sucked in......

[Q451990]

I really don't think there's enough of a vacuum there to pull grains of sand in...

Heath

[Q45tech]

Really wish members would get use to using "pressure differential" instead of 'vacuum' because 18" of HG is still [0.6 x 14.7 psi] =+ 8.84 psi in the plenum or engine.

A vacuum is a complete absence of any pressure and we really see this on Earth.......now vacuum down an AC system is a valid use of the term since you are trying to boil off the water vapor in the system by an extra ordinary pressure reduction

Separates the auto mechanics from the engineers/technologist

[pito11213]

OK Tech......So what is the bottom line about leaky valve covers? What are the negative effects of leaving them leaky for too long?

[elwesso]

Negative effects that I can think of are having a mess, smoke, and evetually it could catch fire.....

[AlabamaDan]

OK Tech......So what is the bottom line about leaky valve covers? What are the negative effects of leaving them leaky for too long?

I guess the only negative effect I see for leaky valve covers is a messy engine if you keep the oil checked regularly.

[Q45tech]

Oil covers O2 sensors and could cause problems, rarely seen or diagnosed.

Just part of the being a good owner housekeeping.

[Chally]

Separates the auto mechanics from the engineers/technologist

No, just talking in a language ALL can understand. If I spoke to my customers in such manner, they would think I'm nuts!I wonder what we should re-name the Vacuum Cleaner, the New Pressure Differential Cleaner...

[osas]

Hi, just wondering if you still have the valve cover gasket for Q45. mine is a 1994 year. And one more question, did you change yours yourself or do you think I can change mine? My car has the traction system and mechanics say that because of it I will pay more to chane both. What do you think?

[elwesso]

You can get them from Joe at scottsdale.. 1 888 216 5328

About $15 each... You can DIY easy..