I have been known to use Rislone engine treatment on older engines (with un-known service history).
I remove and replace the oil filter, then add the quart of Rislone. Drive it for a day or two (to get things good and hot) and dump the oil. It makes a world of difference to the cleanliness of the engine internals.
It says you can just add this at oil change time, but I don't like to run it the full 3K miles; just long enough to heat up the engine and clean the gunk out. Nasty-a$$ engines will need a couple treatments. |