Flushing a engine block that has been sitting.

[Tony_H]

Well here is what I did. I replaced the O'Reily water pump with a Flowkooler pump. While I had the pump off I poured a 1/2 bottle of CLR into the water pump holes on each side of the block then let it sit for a hour. I used a water hose to flush out each side of the block. Man the stuff that came out. I repeated this step again using another bottle of CLR. Once flushed, I put it back together and installed a Bob Drake filter in the upper hose to catch the big stuff. Now the engine runs 180 to 190 degrees without any issues. I have drained the straight water 2 times now and it is still turning nasty brown. So I'll keep doing this until it clears up then it will get 50/50 distilled and antifreeze. I hope this helps someone. I wasn't looking forward to pulling the engine.
I have a nice ugly stain on my driveway, so if you have to do this make sure you wash down your driveway good.