hot to perform cooling system pressure test?

[76er]

I have a 1976 mercruiser 140, i checked the oil and its a tan creamy color. Im not sure if i have a cracked block, head or exhaust manifold. i read doing a cooling system test would tell me the answer. how is this performed? any other ideas would be welcomed please. Thanks

 

[Don S]

Re: hot to perform cooling system pressure test?

Drain the water out of the cooling system completely. Then block off the hose going to the exhaust manifold, and the transom intake hose. Then pressurize the block and listen for air leaks.