i havn't heard of it...i do use full synthetic oil though (not just synthetic blend) and i havn't heard anything that i would call 'valve chattering' -- and i obviously don't use this 'stabilizer'
Lucas oil stabilizer is just an additive that thickens up the oil, I'm not too sure but my own theory is that this may change the viscousity and weight of the oil, making it too thick. maybe not.
IMO, don't mess with your oil. Just use good quality full synthetic & call it a day. Anything that covers up the sound isn't doing your motor any good.
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