Just curious has anyone sealed the water jacket in a cylinder head using POR15 or gas tank sealer. Just thought it would be an effective way to seal for rust and or pinholes. Don't know if it would effect the cooling any. Thanks, John
Cooling is accomplished by the water being in direct contact with the material being cooled. POR 15 may act as an insulator. Others may have a different opinion
Almost anything you can put into a head, to seal the water passages, will be an insulator of some sort.
Thinner materials, such as POR 15, will most likely insulate less, whereas thicker materials, such as gas tank sealer, will tend to insulate more.
How much insulating character will cause heating problems, I can not say. I would definitely NOT recommend gas tank sealer. It makes a fairly thick coating in most cases.
Shouldn't have any rust if your running antifreeze. I'd patch a pin hole or freeze crack on the outside of the block with Ultra Black.
FWIW there is a reference in the Ford reminiscences to using 'water glass' to seal imperfections in water jackets of new block castings. That applied to the pre-T blocks that were supplied to Ford plant for assembly. I would be careful using this method, and I would never use 'water glass' in the radiator. jb
I would never use 'water glass' in the radiator
Why not? People have been doing it for years.