Quote:
Owen_Dyneto wrote:
The symptom here that begs for an explanation is the OP's comment that the lifter noise goes away after about 15 minutes, by which time the oil is thinner and pressures are probably lower, especially at lower engine speeds. So what's the explanation for that observation?
Good point. One possibility might be too much clearance between a lifter and tappet body letting the oil leak out before the lifter is filled and it is taking a long time to get enough volume in the lifter to pump it up. Another might be dirt or a bad ball valve in a lifter that can't seal very well with the same long time needed to fill the lifter.
If it is more than one that is noisy, possibly the overall pressure or volume is low due to wrong weight oil, wear, or sludge blocking the pickup. Another possibility is the timing chain valve is stuck and too much oil is bleeding past the valve into the timing chain so it is taking more time for the lifters to fill. Any aeration if there is too much oil in the crankcase could also be an issue.
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