Thread: Engine clatter
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Old 08-21-2012, 09:57 PM
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Re: Engine clatter

When coolant contaminates the oil, it eventually works its way into the lifters. Coolant is thinner than oil, so when it gets in the lifters, as soon as the cam lobe pushes the lifter up, it forces the coolant out and the lifter collapses. If in fact this is the problem, when the oil is no longer comtaminated, the lifter will pump up and function properly.

The other end of the spectrum is lifters contaminated with sludge. In this case the lifter will pump up and not bleed the pressurized oil out, the valve will not close completely, and you've got a misfire. Marvel Mystery oil usually fixes the problem. Valve lifters are a "shock absorber" for the valve train. Too sloppy or too stiff will cause problems.
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