Can I use the left over heat in my 3208 Cat engine when it is stopped. By circulating the cooling fluid?

Question

The engine stays very warm for hours after shutting it down. I would like to circulate the cooling fluid with a small 12V pump and heat my boat during the evening.

Answer 1

Sure you can on the port side front behind the alt is a fitting that you can connect to find a plug on the block  to return to> this is used for the water heater if you have 1>

Answer 2

Yes you can do this, but I'll bet you will be surprised how quickly the engine cools, when you circulate the coolant by a heater.  If you decide it's worth it, you might want to have a secondary insulated storage tank that would hold a few hundred gallons of eng. temp. coolant.  that would make your plan feasible and cost effective.

Answer 3

Yes you can, it would be somewhat like the heater in a car.  However you would eventually cool the engine to the point where the thermostat would close and the flow would not go through the engine, or perhaps flow at all.

To make the system work under varying conditions, you would need to have a means to bypass the engine thermostat and also bypass the heater in the cabin.  Perhaps a three way valve, that switches the engine cooling system to a cabin warming system.

Answer 4

Richard's got a really interesting idea, but few pleasure boats have that kind of space in the hull.

I've owned 4 3208T's. Loved 'em for <40 ft. boats. If your boat has a dry exhaust, this is easy. I'm going to be that you don't, however, so listen to .45 Cal. I myself always put a second heat exchanger on so I could run into estuaries where the water temp went over 70, and still work all day without worrying about heat issues. I averaged 15,000 hours between rebuilds, for what it's worth- pretty good. Using bleed heat is good in the summer, too- burns off condensation!

If you want to make things really easy, get a bus heater- they crank out 10-15000 btu, using waste heat from the cooler, and the fans have a really low draw. They're cheap, too, and you can install them without messing with the cooling system.  They last about 5 years, and are cheap enough ($200) that they can be thrown out when they die.