I'm looking for a good oil additive that I can use to quiet down the engine in my 05 Ford focus. I know that many people will say something like "tear apart the engine and fix the problem." Well for me, that just really isn't an option. I'm just wanting to know what a good additive is, that is well known for making engines run more quiet. I'm running royal purple 5w20 in the engine. Thanks in advance!
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