Loosing Antifreeze out of exhaust

[Bigbob62]

We have a Mercruiser Alfa One 170. We have changed the water hose on the back of the engine because it was kinked, changed the exhaust gasket because it was leaking and had the heat exchanger tested (it works fine). There is no water in the oil we did a die test on it. However, we did do a exhaust test on it and we do have fumes exiting out where you fill the antifreeze. Does anyone have any idea what else could be wrong. We assume the thermostat is working and the water pump because the anitfreeze is exiting when we run the boat with the ear muffs on. We have over 400.00 into this boat and still can't figure out what is wrong. Please help!

 

[Don S]

Re: Loosing Antifreeze out of exhaust

However, we did do a exhaust test on it and we do have fumes exiting out where you fill the antifreeze.

Sounds like you have a head gasket gone bad. Not uncommon on those engines. Especially if you had an overheat.
Pull the spark plugs and look at them. One that looks like it just came out of the box indicates it's steam cleaned do to the leak.

 

[Bigbob62]

Re: Loosing Antifreeze out of exhaust

That's what we figured. We checked the plugs they all look dirty and we pressure tested them. 3 were around 150 and one was 120. We did notice a little moisture around the valve cover oil fill cap and the breather tube to the air cleaner. The oil looks clear not milky and we did the die test and found nothing. Thank you for your help.