Try about 1/4 tube of this powder stop leak... It works great..
Put it in the radiator when the engine is cold, then start it up with the radiator cap on and run it for 30 - 40 minutes continuous... As it leaks, it clogs the leak until it's completely sealed...
I use it on fresh rebuilds all the time instead of putting sealer on the threads and it works...
They carry it at most parts stores...
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