Good chance that fewer flushes would have been needed if you'd pulled the block drain plugs to let the rust and scale "out".
Lotsa rust settles to the bottom of the engine water jacket, gets kinda stirred-up during a flush.
When you're done flushing, letting the flush water out of the block drains eliminates the problem of flush water diluting the anti-freeze.
Lotsa rust settles to the bottom of the engine water jacket, gets kinda stirred-up during a flush.
When you're done flushing, letting the flush water out of the block drains eliminates the problem of flush water diluting the anti-freeze.