Quote Originally Posted by vt_maverick View Post
So how is Marvel different from Seafoam? I seem to remember a recommendation from someone (or maybe it's even on the Seamfoam package) to only add the detergent in the last X many miles before an oil change. Agree that you're cleaning the gunk if you put it in at the oil change, but where is that gunk going over the 3-5K miles between changes? Is it just clogging your oil filter that much faster?
I've read the same thing about using fuel system cleaners like the stuff from Chevron with Techron. You run something like that in the last tankful of gas before oil change time for the exact reason you stated.