roberr54,
I have used almost those same methods myself. The Dexron in the GM spec ATF is suppose to be the additive that attacks varnish, etc and holds
it in suspension until the oil is drained. A dose of ATF was the secret cure for noisy hydraulic lifters.
There are modern day engine flushes available at your FLAPS. I have used these and they seem to clean the engine to some degree.
Standard Oil Company used to make a product called PDQ Engine Cleaner. It was nasty, but did a hell of a job...if the engine survived, it was clean. It was sometimes used to clean the internals prior to a tear down and rebuild. I always loved the name...PDQ!
Stuart
