Originally Posted By: Clevy
Running just oil to clean up a neglected engine with real deposit issues will take many,many thousands of miles if it even can clean them up. Sometimes you've just gotta use an additive made for cleaning.
Exactly, keeping an engine clean and cleaning an already truly dirty one are completely different propositions.
Countless pictures of spotless engines posted here, many run on moderate intervals of full syns, have led many to the false conclusion that full syns are a magic cleaner in a bottle. Not true.
JMO.