closed loop cooling

« **on:** October 07, 2025, 04:25:04 PM »

Hello, looking for some advice/knowledge. In my boat I have a closed loop cooling system, the boat runs about 180* I have plenty of water going through the exhaust. I have center rise aluminum manifolds.
I have a relief valve set up @12psi from there it flows through a gate valve then to the heat exchanger. From there it splits off into the manifolds. the hose to the exchanger is 1.0" and into the manifolds its 5/8".
I have no flow out of the relief valve could this be I am pushing too much water out the exhaust?
Sorry for the stupid questions but i am still new trying to figure this out.
Here are the manifolds I am using
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« **Reply #1 on:** October 16, 2025, 10:07:59 AM »

I'd check out the regulator bypass pressure and make sure it's 12 psi. It doesn't take much to foul a regulator with sand, etc.
Why 180?
Mercruiser used to have a 140 thermostat, but later ones used a 160 stat. I'd make sure you have a 160 stat, and even drill a relief hole in it.
I'm not sure that too much water out the center risers is a bad thing, but all I know is logs and snails, and open cooling systems.

Dan'l

Rooster Tail

closed loop cooling

mash on it

Re: closed loop cooling