Word of advice. Never put Royal Purple oil in a high mileage engine (i.e. 300,000+ miles). I ignorantly found out the hard way what the consequences are. A strong Chevolet 6.0 gas engine that sounds a mini snare drum! How do we spell Chevolet again??
Can Hear Every Valve Or Lifter Every Time
Just to be clear, I'm not dogging Royal Purple what so ever. It is exceptional motor oil. Works so well that it will free up any gummy carbon deposits in your motor and all that gunk gotta go somewhere!