1991 Pontiac Trans Am
350 L98 engine 102,000 miles
holley stealth ram intake, comp cams cam(forgot specs for now), comp valve springs, retainers, locks, msd box, edelcrap headers, stock shortblock, no air pump, no egr
700r4 tranny
so i have had this small oil leak first was at the rear china wall, took the intake off and got that to seal up. then i got it running and once it warmed up it was leaking off the rear of the valve cover onto the header (thats how i noticed it first) it also had oil all over the top of the passenger valve cover but not really the drivers side cover? but i am getting alot of oil into the intake. i cleaned it up and took it out for a wot run and got back and left it running and saw it was now leaking out of the centerbolts. so i'm guessing its blowby, and now my question is, is there any way to confirm this? also what would the parts cost for just a re-ring, bearing job with the gaskets? i need to get this fixed as i need to sell it in order to move in just a short time.
thanks

 

Blow by is pretty easy to detect, pull the crancase breather hose out of the top of the right valve cover and see if its spewing vapor. Check PCV valve and hose for buildup and clean as neccessary. Excess pressure should vent thru that hose into the intake under WOT so verify the passages into the throttle body are clear. If you are generating enough blow by to exceed its capacity, you have a big problem but it does not neccessarily mean worn out parts. Frequently the same sludge that plugs a PCV system will cause rings to stick etc.

 

do you have an air pump on the engine still? if not it might be good to look at the bolt holes form the pump removal.

 

yea the inside of the pcv valve is real oily. i have a stealth ram intake so the pcv enters into the bottom of the plenum. so if it is sludge that is causing the rings to stick is there any way of fixing it? no the air pump wasnt on it when i bought it. what would the holes of the bolt removal tell me? would it cause blowby? it is only leaking a little bit and only from around the rear of the passenger valve cover.
thanks

 

that bolt needs to be there or oil will leak out of the block.

 

Are you burning any oil out the exhaust? If you suspect blowby, do a compression test on all cylinders. Check to make sure your oil level is not overfilled.

 

blowby would leak oil internally, if you have any oil noticeable on the exterior of the engine, it's not (only) blowby.

 

no im not burning oil through the exhaust. i am going to do a compression test on it today and see how its doing. i pulled a plug yesterday and it was black like oil but its not smoking through the exhaust. the inside of my intake plenum is also covered in a thin film of oil? i not sure if it is the pcv or what?would it be that i just have oil speeping out of 3 of my valve cover bolts?

 

ok so i removed the pcv while the car was running and there is alot of gases coming out but it doesn't smell like oil. the gases smell like exhaust fumes? so i was wondering if it could be valves that weren't sealing? another reason i don't think it is rings is because it doesn't burn any oil and it doesn't smoke. has anyone else had this or know if this is correct?
thanks

 

Leaking valves don't leak into the crankcase.

Blowby IS exhaust! Makes sense that it would smell like it.

Don't pull the PCV,pull the BREATHER line with the PCV connected. If you have gasses blowing out there, you have an innefective PCVsystem or excessive blow by.

Excessive blowby causes higher crankcase pressures that CAN lead to external oil leaks.

I'm not sure I understand what it is we are chasing here.Are we looking for oil leaks like drips on the driveway?

 

no it just happens when it gets warm and oil just barely seeps out of the valve cover bolts and when i rev it, it gets worse. after a while it leaks down onto the header and starts to smoke but i have only seen a drip here and a drip (on the ground) there so its not like its real bad. i took the valve covers off just a little bit ago and relashed the valves and the fumes were coming from the intake valley. i don't really know where to go from here? any help is appreciated
thanks

 

When I spun a bearing ( just before ) I had oil leaks .... oil would also come up the dipstick . When I would push it down .... the preasure would pop it back up . May be time for a rebuild ?

 

There should be a vent tube venting all crankcase gasses into the intake air stream. If you are creating enough pressure to push the dipstick out at idle, I can't imagine that the breather hose is clear.

 

yea it not pushing my dipstick out but it is creating quite a bit of pressure. i don't understand, if it was blowby wouldn't i get smoke in the exhaust? i don't have any smoke coming from the exhaust. i did check the vent tube and it is clear. are you any sure fire ways to tell if it is blowby?
thanks

 

cylinder leak down test

 

Blowby is cumbustion gasses leaking past the piston, oil smoke is caused by oil leaking past the oil control rings, you can certainly have one without the other. A CLT (Cylinder leakage (leak down) Test) will tell you where and how much.

 

What if the intake gaskets were leaking at the egr port in the cylinder head?

 

Its a 6yr old thread.