Crankcase Venting.

[jafo]

I just got done with a rear main seal today. Drove it, then parked it for 30 minutes and found a small drip on the floor. It vame from the drivers side rear. The entire pan was dry as a bone but above it the backside of the block is lightly coated in oil on both sides of the block. I believe it to be the valve cover gaskets causing this. But it got me to thinking if the crankcase wasn't venting properly, it may push oil pass seals. So I pulled the hose from the oil fill tube breather that goes to the air cleaner. I started the engine and got very little if anything coming out. When I increased the rpm's, it actually got vacuum. Is this the pcv valve at work on the other end of the manifold? It's a '79 AMC 304 .

 

[Scorzany]

Air comes from the air cleaner. Not to it. You could have bad pcv valve. They are cheap. Change it.

 

[Lumpy Grits]

Replace your PCV valve-They're cheap.
What weight engine are you using?
LG

 

[Torxhead]

I would suggest a crankcase breather to fit into the valve cover to relieve the excess pressure.

 

[jafo]

Running 10W30.

Pcv vavle is new.

I'm really not sure there is a problem.

Going to put new valve cover gaskets on today also.

 

[Scorzany]

The PCV System

Read that....

 

[jafo]

Valve cover gaskets were leaking badly. Retainer bolts for covers were less than finger tight. Used some good ole aviation sealer on new gaskets and installed star washers on all the retaining screws. I also noticed while replacing rear main seal that the dipstick tube looked to be at an odd angle. I have been overfilling the crankcase. I finally crackes the repair manual out and founf that it takes 5quarts with new filter and 4 without new filter. I have been puting 6 1/2 quartw in. That's where it meets the full mark on the dipstick. Drained a quart out and replaced valve cover seals and found a dry floor this morning. So it's not blowing by the seals.

I'll take a look at the link on venting too.

 

[Scorzany]

Awesome! Happy you found the cause of your issues.

Thanks for posting the cause and resolution to your problem and in such good detail. I learn a lot from other peoples problems but only if they do what you did and explain the cause/resolution sufficiently (or someone else does LOL).

I don't know what I would do without this forum!

 

[Lumpy Grits]

Glad you found it.
LG

 

[mtnwhlr]

Having a qt more oil then it should have could have been part of your leaking problem.

 

[jafo]

Very well could have been part of the issue. It's been getting that amount since I bought the jeep over a year ago. I liked it so much it's my daily driver.