2002 Mazda Millenia Repair Question
Mazda Millenia 2002 with 90,000 miles.
If the leak is from the valve cover, I don't think it is due to the oil you use. When replacing the valve cover gasket, if non OEM gaskets are used, they might leak. The other thing is proper torquing. Improper torquing can result in the valve cover cracking and leaking. Recheck the work done.
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