how much diesel do I put in an engine to clean out the sludge?

I am an old timer. I use a mix of one liter of automatic trans fluid. 2 liters of deisel and the rest oil. I have run cars on pure deisel. Just don't rev it. Let it idle for about 2 minutes then do an oil change.

Diesel is more or less a solvent! It would seem, a solvent would also cut your oils lubricity - while cleaning. I heard people say, "try transmission fluid," also a really poor cleaner - and transmission fluid thins out your oil. That sounds like less lubricating to me - how about you?

In the old days, motors use to be torn apart every two years - because of sludge and wear problems, then overhauled. That was the way it was. Solvents did clean some - and caused engine damage some. But who cared - you were about to have it torn into and rebuilt, anyway.

They sell solvent flushes at parts stores - the same guys who sell you new engine parts -mmmmm. Wonder why, if its not good for motors? Today's motors go 10-15 years before being overhauled. See anything wrong about putting in diesel - a solvent, when you want to protect your engine's life?

Today's new flush "chemistry flushes" have no solvents in them and clean marvelously. They themselves are an engine treatment - which means, the best ones advertise friction -reduction and problem-solving advantages - look for those type engine cleaners on google. Try them to flush your motor safely. That's my take - I'm a mechanic - I see too many damaged engines from lube joints selling customers solvent engine flushes, too. I wonder who pays for that damage a month later?

Use Marvel Mystery Oil it really keeps the engine clean.Ive dissasembled high mileage engines that used it and the engines looked like low mile engines inside.

It was one quart of diesel.