Lake Water Temp.?

[Escape26]

Before all you guys start yelling at me I did do a search on this topic. I was wondering if it's bad to run your boat when the lake gets close to freezing. I know rescue boats run in cold water but I wasn't sure if they had some closed loop cooling system that kept the temp up. It just seems like the engine wouldn't like ice cold water rushing in after the thermostat opens. I'm swapping a 4.3 with a 5.7 in a 16 classic and I don't think I can wait untill spring to try it out. Should be done by the end of Oct. Thanks for your thoughts and sorry if this is an old topic.

[BigGrizzly]

It is ok if you have a thermostat and it is warmed upwell. Don't jump on it cold. If you have a closed colling it is no problem.

[MOP]

The Tstat does not snap open it regulates the flow to maintain the desired temperature, not to worry but like Randy says let it warm up under light load until warmed up.

[Pismo]

The raw water in always mixes with the block water in the thermostat before it hits the engine. In older apps it is preheated thru the manifolds.