Coating Coolant Passages?

[bluewavecaptain]

I have a 1977 Volvo Penta AQ280 mated to a Ford 302 engine. The engine is the original and most of the components, such as the exhaust risers are, as well. I'd like to keep them, if possible. I haven't torn into the the engine, yet, to see if everything is OK. My question is, is there a product to coat/paint the cooling passages in the engine and the exhaust risers to keep them from rotting out. The boat has operated on the Great Lakes it's whole life and will continue to do so. I'm not even sure if it's work doing? Am I overthinking this or overdoing it? I just want to keep everything in good shape. Thanks for all your help.

 

[Scott Danforth]

Any coating will lessen any themal transfer. If you have never been in salt water, you can flush the water jacket and add a heat exchanger.

If you have been in salt. Its a bit late. Just go boating