The Stovebolt Site Forums The Shop Area Engine Shop Perferred water coolant cleaner, 235 engine.

Phones don't like words like petcock. They also don't like cock-a-doodle-doo. The last time I had this problem with a 235 I first removed the petcock and pushed a coat hanger wire up and through until I got a small dribble. You will need to bend it to make it go through...going straight in will not work. This will be encouraging to you but you can only go so far with this scheme. Next I replaced the petcock and removed the water pump and poured CLR undiluted into the block until it reached the highest point it could go without running over. Then I left that for a day. CLR loses its strength as it does its work. By now you can appreciate the reason for using the coat hanger to open up the area a bit...I needed a way to let the CLR out. Then I drained the stuff out and repeated this again, leaving it to sit another day. Then with all that drained out I poured CLR in there to about 1 inch from the top of the water pump opening, got my coat hanger and worked it back to the very rear cylinder (through the water pump opening). I put a bend in it and twisted, poked and prodded until I was able to dislodge as much of the junk as possible, removed the petcock and let this all drain out. Then I repeated that last procedure a couple of times until I got things as free-flowing as possible. Then just because I had about 1/2 bottle of CLR left I poured it in and left it overnight. It took care of as much of the problem as I needed. Good luck!