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PCV valve replacement questions

11K views 6 replies 5 participants last post by  mddombrowski 
#1 ·
I read that an indicator that a PCV valve is bad is excessive oil consumption and oil leaks, which I have been experiencing the last couple of years. I also read that you can test to see if a valve is bad if it doesn't rattle when you shake it.

I replaced my original 13 year old PCV valve at 112k miles with GM part #12574660, which included the PCV valve and the hose.

When I removed the old valve and hose assembly, the valve was able to be removed from the old hose easily. I heard no rattle when I shook it, so I figured I found a bad valve. However, I also heard no rattle when I shook my new valve and hose.

When I looked inside the old valve, it is just an empty chamber. There is no ball valve inside like I expected to see, so there is nothing to rattle. The new valve is attached firmly to the new hose, so I didn't remove it to look inside, but I assume it also doesn't have a ball inside if there is no rattle when shaken.

Am I missing something here? If it is a "valve", how does it open and close?

Also, the other end of the PCV hose attaches to a plastic nipple connection on top of the engine near the intake manifold. How is that part removed to inspect and clean it?

Thanks!
 
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#3 ·
rattle/no rattle not conclusive

I can't speak to this application specifically, but many sites warn that the "rattle test" for a PCV valve is no longer accurate (if it ever was). The valves are (lightly) spring loaded and actually fairly sophisticated -- it's not just an open/closed function. Good idea to replace the old part, and I wouldn't worry about the rattle (or not) on a new one, as long as you don't notice any strange idle or off-idle behavior by the engine.
 
#5 ·
5.3 will have the fresh air valve on the right side cylinder head cover which draws air (via vacuum) through the air resonator near your oil fill cap. The crankcase vent (with PC valve) is on the left side cylinder head cover and draws via intake vacuum into a port on the intake manifold.

These are spring loaded valves. The rattle test of yesteryear is no longer valid with this type of valve.
 
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