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Burning Anti freeze during warm up

jon_allen

Regular Contributor
"Hi All,
My buddy's got t


"Hi All,
My buddy's got twin 1996 MIE FWC 350s in his boat. The port is burning a small amount of antifreeze as it warms up. You can see it and smell it and the overflow bottle is going low. Any ideas? I'm thinking poss. man to riser gskts but maybe thats wishful thinking. Thanks in Advance.
Jon Allen"
 
I didn't think antifreeze

I didn't think antifreeze was plumbed into the manifolds but rather raw water. Sounds like a head gasket.

Any coolant showing up in the oil? What happens when you pressure test the cooling system (engine off cold)?
 
"In a complete FWC system, ant

"In a complete FWC system, antifreeze circulates through the exhaust manifolds. Checking/changing the exhaust manifold to riser gaskets would be a good guess; replace them and you will know right away if they have failed. Then pressurize the cooling system with a hand tester. Pump it up to 16-20 PSI and see if it holds for 10 minutes. The heat exchanger would be my other guess since it is prone to corrosion of the cooling tubes expecially in salt water.

Let us know what you find."
 
"I had changed my risers last

"I had changed my risers last year and obviously did the close off gaskets too between the risers and the manifolds and this year I'm still getting antifreeze burning during a startup. It makes snese that coolant may drain down through the gasket into the manifold and burn, but I'm sure the gaskets are sealed and torqued as per specs at 26 ft-lb. So what else could it be? Manifold gasket? Manifold? There's no coolant in the oil, so this is just exhaust area. Ideas? Thx."
 
Welcome; you need to post a ne

Welcome; you need to post a new thread so you get more viewers. Include year and pertinent engine info. Did the problem just start or before riser change?
 
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