Join Date: Sep 2003
Location: Auckland New Zealand
Thanked 35 Times in 32 Posts
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Sorry to sound contrary Sailingdog but any closed cooling system needs to shed heat and this can only be done through some form of heat exchanger. In an automobile, the heat exchanger is in the form of an air cooled radiator. In a boat it is done through a heat exchanger that has coolant on one side and raw water on the other. I have never seen any other form of cooling system and I've surely not seen any boat with an aircooled system.
If it needs raw water, it will splash out of the exhaust (unless the exhaust is underwater - rare).
I agree with previous thread that a closed system will allow quite extended running before causing damage (maybe not 20 minutes!) but this will definitely show on the temp guage (unless of course that's faulty as well). Another contributor to running longer will be if the hot water cylinder is also in the form of a heat exchanger, this will absorb quite a lot of heat energy depending on it's size as will a refrigerant heat exchanger. Lots of variables.
This is surely a strange one. If the fairer is going to be keel hauled, hold him down there long enough to put another strainer on.
I never allow my engine to run more than a minute without seeing water puffing out.
Last edited by Omatako; 06-14-2006 at 04:15 AM.