496 HO | Head Gasket Problem ?
 

Looking to purchase a 2004 35' Executioner with 496HO. I had the boat surveyed today and noticed the port engine had green & pink coolant in the reservoir and the tank seemed to be dark almost like a carbon deposit? The ecm showed no over heating or related fault codes. The surveryor stated is could be a head gasket starting to leak causing the tank to be dark. Could this be true? Both engines have 180 hours and the water pumps & housings were replaced at the end of last season.

Thoughts?

Dexcool (pink) + norm green antifreeze can cause darker crud (over time) when mixed,

Has the antifreeze ever been changed on those engines?

The antifreeze is only good for about 7 seasons, tops. Less with higher use. After 7 seasons it will start to darken, getting a carbon/metallic type of shade; AND it will silt up, not flow as well and cause the engine to heat up. I've posted about changing antifreeze on the 496 Mag and 496HO before; and you should be able to find some other posts.

Also, I would be less concerned about a compromised head gasket, and more concerned about a compromised heat exchanger.

Last, it should have NEVER had green coolant added to that engine.

I agree with Brian, most likely old antifreeze that was never changed. However, if the surveyor was concerned I am not sure why he didn't test the antifreeze for combustion gases, here is an example of a tool....but there are even cheaper options for testing at local auto parts stores. If the head gasket is blown, exhaust gases get in the coolant and this will detect it.

http://www.nationaltoolwarehouse.com...FacF7AodezoAzw

Thanks for the input - they are to pressure test the system tomorrow.

The crud is normal. The bigger problem is why was antifreeze added??? They are so low maintenance it is ridiculous. I put antifreeze in my boat 1 time. When I rebuilt the engines.... Maybe flushed the log out once due to an impeller issue but still only had to add a half gallon of pink stuff.

Back to the crud, my bottles had stains and deposits at 200 hours and I tried to flush them with every method known to man and didnt have luck.

No idea...

I know at the end of last season they changed the water pump & housings. The boat sat wrapped all winter. They cut the plastic for me to look at it two weeks ago. Last Wednesday they go it ready and put it in the water for the surveyor. It almost looks as if it was added my accident as the green coolant is sitting on top of the pink.

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Here are two photos showing the darker coolant tank...

Almost looks like oil. My 496 is 11 years old and the tank/coolant still look new. 400 hours.

Which in this engine would be indicative of the head gasket leaking?