Milky oil Mercruier 3.0 / how to pressure test engine ?

[Franco_boater]

Ciao my friends,
I know its quite common problem so I have decided to create this thread...
When drainin the oil it was milky, like a brown coffee.
Engine runs fine so I dont know why there is a water, how to pressure test the water passages to check if the head is OK?

 

[Scott06]

to pressure test the cooling system you need to take the water inlet hose and water outlet hose to the manifold , plug them with pipe fittings such that you can pressurize with compressed air and have a pressure gauge.
you should also check the manifold and exhaust elbow as these can leak especially at the manifold to elbow connection. They can be checked by filling with acetone as it will wick through cracks .

 

[Rick Stephens]

You can also pull the elbow and make a block off plate to cover the surface on the manifold and test it at the same time. Use a piece of rubber and some sealant.

 

[Franco_boater]

You mean to pressure it? I was thinking about acetone test

 

[Scott06]

You mean to pressure it? I was thinking about acetone test

Yes Rick means as an alternative to acetone test, so you don't have to remove the manifold as you would for acetone testing.

Make a blank off plate for where the elbow goes and pressurize with air when you do the block testing.

 

[Searay205]

my guess is one of your exhaust passages in your exhaust manifold has thinned and cracked. hot exhaust gas on one side, water on the other, erosion corrosion.

 

[Rick Stephens]

You mean to pressure it? I was thinking about acetone test

You will need to pressure test block. And to test manifold you either remove it and do acetone test or leave it on, block off the exit and pressure test it with the block.