By: Grid Michal
I have a 1990 350 Chevy Mercury motor with water in the engine oil. I removed the intake manifold, the exhaust risers, the exhaust manifolds, both heads, the cylinders and walls, and found the same color on all eight. All of the spark plugs (eight) look the same, with no indication of water. I filled the block, the risers, the exhaust manifolds and the intake with water, and saw no sign of cracks. I did see a rust stain on the intake gasket at the water port on the head (front).
As far as the engine, while all the components are off, you should take them to a radiator/machine shop for pressure/leak testing. If there’s a crack, you won’t find it while the engine is 1) cold or 2) non-pressurized. If you have a transmission cooler line, that’s another place to have checked. The best thing would have been to pressure-test the entire engine while it was together. It may even have a crack in the block from ingesting that marvelous New Jersey salt water, and now you won’t know until you pay the testing bill and reassemble it all.