Oil on top of intake

[LanceB]

I noticed little oil pools on top of the intake under the carb. What are some possible sources for this? It is on both sides centered around the bolts on the intake....:confused

 

[spikebot 81]

My first guess would be failed pcv valve sucking oil from the valve covers. Are you useing after market valve covers?

After rereading your post I thought you ment inside the intake under the carb. Sorry my mistake.

Oil can wick up the intake manifold bolts and leak out between the bolt head and the manifold. Where is the oil visable? Sides of carb,front ,back?

 

[LanceB]

Stock valve covers, would like to take off and paint them, but don't appear to be leaking from there. It is pooled around the middle 2 bolts on each side right on top of the intake underneath the carb. There appears to be eight of these bolts on top of the intake, but just the center two of each side have visible oil around them.

 

[spikebot 81]

I agree, the valve covers normaly leak at the bottom rear by the exhaust towards the firewall. I cant remember if the center bolts on the intake are tapped through to the lifter valley. But I'll still stick with oil wick up the bolts. If the intake hasent been off the engine for many, many miles you would be best to pull it and replace the intake gasket and use thread seal on the bolts. I use permatex formagasket sealer for the bolts.

Hope someone else chimmes in with more brains than me

 

[Crimson Thunder]

I agree,its coming up through the intake bolts.Just take the bolts out and apply sealer(i use Permatex #2) and it should solve your problem.

 

[GTR1999]

I use #2 or high temp thread sealant which is cleaner. Common problem.

 

[TMPJoe]

i agree its a common problem especially with aftermarket manifolds.. the chrome ones can be bears to get to seat properly

 

[C3RVETTE]

My problem is oil leaking out around the valve cover grommets

 

[spikebot 81]

My problem is oil leaking out around the valve cover grommets

I have bought new rubber gromets at the auto parts store and some gm dealers

 

[C3RVETTE]

I have bought new rubber gromets at the auto parts store and some gm dealers

So did I. Maybe some silicone,if I can hide it

 

[Rodney Gold]

There should be a baffle plate under the breather openings in the valve covers to stop oil spash, if the grommets are "leaking" it could be due to an inoperative PCV system or the motor breathing excessively.

 

[fm1]

You guys know the old saying, " show me a Chevy that doesn't leak something somewhere, and I'll show you a car that doesn't run "

 

[C3RVETTE]

There should be a baffle plate under the breather openings in the valve covers to stop oil spash, if the grommets are "leaking" it could be due to an inoperative PCV system or the motor breathing excessively.

Ironically,I installed the baffles that came with the aluminum 'flamed' covers when I got them

 

[GerryLP]

There should be a baffle plate under the breather openings in the valve covers to stop oil spash, if the grommets are "leaking" it could be due to an inoperative PCV system or the motor breathing excessively.

The baffles do hold some of the misting back from coming out, but I would recommend to check the positive crankcase ventilation system. If, for example, you were to have leaky valve covers, the effectiveness of the pcv system will be deminished.

The way it works in most chevy V8 engines is that clean fresh air is fed through at the RH side valve cover, and the vacuum source connected to the pcv valve side (usually the pcv valve is on the LH side valve cover) , and the fumes enter the fuel induction system somewhere downstream of the carburetor for re-burning.

If the vacuum signal seeems to have diminished, then quite possibly there may be a vacuum leak somewhere in the carb gasket, or connecting hoses.

The vacuum signal keeps the oil fumes from oozing around the interconnecting parts.

By the way, a functioning pcv system keeps the engine running healthy.

GerryLP :cool