Went out for the first sail of the season and my temp gauge pegged hot. .. didn't do anything since last year so was caught off guard.
I checked the"clip on" wire to the thermostat and that was still attached. The fan belt wasn't loose and there was plenty of anti-freeze. I have not yet changed the impeller but when I went under the boat it seemed to be pumping water as usual. This suggests to me that the water intake isn't clogged and the impeller is working.
The only thing left I can think of is the thermostat. Any other suggestions, and if it is the thermostat, how difficult is it to change?
Thanks
Chuck Parker
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Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ
If the temp sender wire is shorted to the block it will peg the temp gauge hot. There are two senders on my M35, one for the gauge and one for the overheat alarm. If the alarm is not going off, check the wire to the gauge. I had mine pinched between the alternator and the block causing it the chaff through which caused this problem.
Ron St. Onge
1995 Catalina 36 MKII Hull 1384
The first thing to check is that you're getting plenty of water flow out the exhaust. If not then you have a clog or constriction in the cooling system somewhere.
I recently had an overheating problem and noticed that I was getting very little water out the exhaust. The intake did not appear clogged. The impeller was in good shape. I fixed the problem by removing the hoses from the raw water pump and poured descaling fluid (muriatic acid) into the hoses and let it soak. Got a fair amount of lava foam coming back up the hose so be prepared for the reaction (and pour slowely). After letting the acid work for several hours flushed with water and reattached the hoses. Now I get plently of waterflow out the exhaust and a steady 165F engine temperature.