fourydlx:
I tried to find "Wood Bleach" by DAP with no success. I did fine Wood Bleach by Savogran at ACE hardware. It is sold in 12 oz containers and you mix the entire container with one gallon of warm water. I have started a controlled test of the product. I had two water pumps and a thermostat housing that had quite a bit of rust on them. I did not wire brush them or clean them in any way to simulate the areas of the water jacket that are inaccessible. I mixed two containers of the Wood Bleach in 2 gallons of water and placed the water pumps and thermostat housing in the solution. So far I took, pictures each hour for the first 4 hours and then again at 8 hours.The pictures are at 8 hours. I am planning on leaving them in until they are completely rust free or the solution has been neutralized (at least 24 hours) . I am working on a block that has been cleaned and magafluxed so far and found to have no cracks. The block had no external rust that couldn’t be removed with a wire brush on a 1/2" drill, do I did not feel the whole block needed to be dipped. This will be the replacement engine in my 53" Merc. I have installed a second set of old heads with old gaskets on the block and blocked off the thermostat housing and stood the block up on its back. I will fill the water jackets and leave it for at least 24 hours then flush out the jackets with a hose and water. By the way the entire cooling system is around 6 gallons, and I have discovered the each water jacket is 2 gallons, therefore it will require that I buy 4 containers of the Wood Bleach. Unfortunately I have been unable to find it in the 5 lb container. When I started, both water pumps were locked and now they turn freely. I will post additional pictures.