Reader Question: I have a 1995 Ford F-150 with a 300cid 6-cylinder engine. I have a crack in the block and it is leaking coolant this crack is about 4″ long.
You can see the water seep out of the crack as I run the engine will this K-W stuff work for this too? Should I use two cans instead due to the size of the engine? Or, will it work at all? Would this stuff harm the radiator (it is new)? It sounds promising.
Thanks for your e-mail and your insurance quote.
Honestly, I think it is going to require a new engine block, BUT this additive is cheap and something you can do yourself. I will not harm any other components like the radiator, so you might want to at least try it. This additive is made to work on internal leaks, since it needs the heat from the engine to harden.
I have never tried in on visible external leaks before, so if it works please give me a shout and let me know.
To use the K7W Block Sealer:
Drain out the coolant from the system and install ONE can of additive and top off with water and drive at least 500 miles then drain and install coolant and water mix. Do not follow the instructions on the can it does not work, or at least I have not had success with how they tell you to use their product.
You might want to visit your local machine shop or welding shop and ask them if they can weld up that crack, you see. JB Weld might also be worth a last ditched attempt to seal this leak.