I have a 88' 7.3. It has a coolant leak right above the front drivers side motor mount, it isn't the water pump. I was thinking it might be the block, or a freeze plug leak, or the block heater. I used some "aluma seal" this worked well, and actually stopped the leak! Then I took for a test drive then it was leaking either engine oil or radiator oil, directly from inder the radiator, then after a few more resarts it was pouring coolant. When it is shut off the coolant leak pulsates. Like it is building up pressure then squirts out a thin stream. Any ideas? Thanks

 

does it squirt out with the radiator cap off? Maybe its building too much pressure.

 

It sounds like you have a pinhole in the radiator. Time for a new radiator. It will pulse like if the coolant in the block is hot enough to expand and boil off the water in it. It is building up pressure, releasing it through the hole and building up pressure again.

Don't use any of those magical stop leak gimmics. All they do is foul up the coolant system so badly the leak has to stop. Next thing you know is you are saying hello to a new water pump or you blow a head gasket because the radiator is clogged with that crap.

Flush the system out very well to get the stop leak out as much as possible. Replace the radiator with another copper/brass one for best performance and reliability. The aluminum ones are hit or miss. Replace all your hoses and make sure every hose clamp is tightened properly. Refill with Fleetcharge antifreeze 50/50 with distilled water. There are multiple threads on overhauling the coolant system, just do a quick search.

 

Oh, and there is no such thing as radiator oil. If you have oil in the radiator, you have bigger problems than just replacing the radiator.

 

The oil cooler is right above the driver side motor mount. It is an oil to antifreeze cooler. If it leaks it can put oil in water and water in oil. It can also leak either. I would check to make sure you don't have antifreeze in the oil to be safe.