Valve stem seals pontiac
Okay, I have been stunned. Took apart my heads and apparently the valve stem sealing is accomplished by an O ring and a bunch of grooves that are machined into the valve stem hole. Just did some research and found that installing positive seals or a bronze guide would require $machine work$. However, I am wondering, since GM designed it this way it must work, so how do I know if I need to replace anything or not?