how to fix tappet sound
Is it a tapping/ticking sound? If so check the valve and valve lifter, and the oil pump, those could be the source of tapping or ticking.
If you just want to quiet it down, there's an additive you can buy at the auto parts store, but it's only temporary, if you want it done right you may want to do what light gear mentioned, if you replace your lifters? You also may want to inspect your cam lobes if you need new ones..
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