2000 Dodge Caravan Base, 3.0L Mitsubishi motor (aka Oil Burner), just got this in January used w/150k mi. Put in 5qts Carquest 10w-30 (essentially is Valvoline since they package it for Carquest), Wix Filter. Wondering if I should do an oil flush next change just for good measure to clean out the engine and switch to syn 10w-30, same filter. Thoughts?