Originally Posted by Kuhl
Russian, I think that what happened was not due to the slick 50 but due to the fact that you were changing your oil regularly.
Ayup. Regular oil and filter changes _will_ clean up a neglected engine. I've picked up more than a few old cars and given them 500-mile (yes, five-hundred-mile) oil and filter changes, and after a couple of rounds like that, the oil stays cleaner for much longer, and the engine sounds obviously better as well.
Skip the miracle sludge cleaners and just go a couple of short-term oil changes instead. It'll work. (I'd say go 1500 miles between oil and filter changes until you see improvement.)