Quote:
Originally posted by sjf911
I don't quite understand what you meant by your leak down numbers.
Worn valve guides will typically cause smoking on deceleration and idle while driving, not so much at start up. They typically won't affect compression or leak-down unless really bad.
The valve failure risk comes from loss of contact of the valve stem to the valve guide resulting in lack of heat transfer, I don't think frequent oil changes are going to help there. There is a good chance that one or more valve stems will be worn out of tolerance as well and need replacement (not that costly).
Once you suspect valve guide wear, I would not delay as your risk of catastrophic failure is rising. I would also recommend replacing any worn valves even if still within tolerance (I would personally replace them all).
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Steve,
I'm new to all of this, and I'm still trying to get it straight in my head. Ultimately, the mechanic did in fact say that the leak down numbers were very good. One cylinder had a 6% leak and the rest were in the 1-3% range. His conclusion, in spite of the results of the leak down test, was that the valve guides EVENTUALLY need to be replaced. He said he concluded this based on the car smoking on idle and more than normal on startup. He also had the valve covers off and was able to inspect it.
I'm not mechanically minded so I don't espouse that I understand his conclusion thoroughly, but I do trust his judgment as his reputation goes before him. Is there a particular question I could ask him to better gauge how long I have before I should replace the valve guides? It seems to me that if a poor leak down test is an indication that the valve guides need to be replaced, and since my leak down test came back very good that I should be OK for a bit. Please correct and critique me if I am wrong in such thinking.