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Discussion Starter · #1 ·
Aye....what's up guys? I have, what seems like, a small oil leak coming form that thing that sticks out of the top of the passenger side valve cover... What is that thing? Mine doesn't seem to fit very snug...
 

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Its the PCV fresh air vent. Go to a parts store and look for a new grommet for the valve cover, usally in the help section. The grommets get old with age. Sometimes they are a bit difficult to remove but a big flat blade screw driver pops it out easy. With a new grommet it will be snug and wont weep oil.
 

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Discussion Starter · #3 ·
Its the PCV fresh air vent. Go to a parts store and look for a new grommet for the valve cover, usally in the help section. The grommets get old with age. Sometimes they are a bit difficult to remove but a big flat blade screw driver pops it out easy. With a new grommet it will be snug and wont weep oil.
10-4. What exactly does the PCV vent do?
 

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10-4. What exactly does the PCV vent do?
Its just like a breather. But since the EPA were involved in automobile design, instead of crank case gasses being vented to the atmosphere, they are vented inside the engine (well, when the throttle blades are not fully open) Even PCV system needs to be vented some how. If you plugs that hole in the valve cover then plugged the tube on the throttle body at the other end the PCV system would not be doing its job to vent the crankcase. Thus Oil leaks, reduced oil life from excessive blow by gasses and oil consumption could occur!

The way its plumped on a LT1, If you have an air / oil leak at that grommet, their will be a slight vacuum leak because that hose is attached behind the throttle body. On a Throttle body injected caprice, 91-3, The same hose goes to the AIR box, behind the air filter (filtered air) then back into the valve cover.
 

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Discussion Starter · #5 ·
Its just like a breather. But since the EPA were involved in automobile design, instead of crank case gasses being vented to the atmosphere, they are vented inside the engine (well, when the throttle blades are not fully open) Even PCV system needs to be vented some how. If you plugs that hole in the valve cover then plugged the tube on the throttle body at the other end the PCV system would not be doing its job to vent the crankcase. Thus Oil leaks, reduced oil life from excessive blow by gasses and oil consumption could occur!

The way its plumped on a LT1, If you have an air / oil leak at that grommet, their will be a slight vacuum leak because that hose is attached behind the throttle body. On a Throttle body injected caprice, 91-3, The same hose goes to the AIR box, behind the air filter (filtered air) then back into the valve cover.
Ahhhh...out of curiosity, could I lose any horses or hear any weird noises from this?
 

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Need to bump this topic. Mine is TBI related. I have installed an air breather filter and done the Cadillac intake mod. Had no problems for the longest, but recently it seems I am having oil leak/force its way out the wedged grommet on the pass. valve cover and is coating the air breather filter. Could this be pressure related? Car otherwise runs fine.
 

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Check the pcv valve (pull out and put your finger over it, should have strong suction).

There will always be some oil vapor coming out of the vent and on to the filter, mine's done that for as long as I've owned it (10 years). It will get worse over time as the rings wear out.
 

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For what they cost, just replace it.
 

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Check the pcv valve (pull out and put your finger over it, should have strong suction).

There will always be some oil vapor coming out of the vent and on to the filter, mine's done that for as long as I've owned it (10 years).It will get worse over time as the rings wear out.
And that's what I think will end up being my prob. Valve doesn't seem clogged when I tested it. I'll try a little Lucas next.
 
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