First of all, my suggestion is for cleaning a sludged-up engine, not for routine oil changes, and it's done at a fast idle speed of 1500 RPM or so, not curb idle. The crankshaft and connecting rods whipping down into the over-filled crankcase act like the agitator in a washing machine and splash the solvent-thinned oil around vigorously. If anything, this process might CREATE leaks, not solve them, especially with a rope seal that has shrunken over the years. The whole idea of the flush is to do a better job of dislodging sludge than can be done by taking the oil pan off and scrubbing stuff with a brush and solvent. Once the crud is gone, then fix the leaks the sludge was plugging up!

A local talk radio host in Nashville Tennessee says he has a bunch of "Van Gogh listeners"- - - - -people who listen to his comments with only one ear, and get the wrong impression about what he's saying. That problem seems to be pretty common on internet chat rooms, too!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!