Posted by Dan H on 5/19/2012, 13:04:03, in reply to "Re: fc 4cyl and 6 cyl radiators"
76.94.254.132
I've had a lot of trouble with thermostats not working or failing. When they fail they fail closed. The worst is intermittent failure. They do make a fail open thermostat but they are hard to find sometimes.. I've run a lot without any thermostat without any issues but never put 100,000 on an engine like that. Just ran them without one long enough to fix whatever the real problem was. If your overheating with all original stuff get a 160 to 165 thermostat see if that helps. Make sure it works at the correct temp with a pan of boiling water and the temp gauge. Still having a problem have the radiator checked there could be some blockage in the rad. If that doesn't work check the impellers on your water pump. I've had a few old ones when you look at them the impellers are all eaten away. While it's off check the water ports from the block. sometimes they get restricted or clogged from calcium buildup.
--Previous Message--
: I would watch the temp. if running with out a
: thermosat, I have done that myself in the
: past, but never again. After I got into the
: marine repair and service end, 23+ yrs. what
: I have seen in a inboard engine, like a 4
: cyl. Gm. eng., small & big block Fords
: & chevy's, if run below aprox. 160
: degree all the time, the cyl. wall wear
: increase and some times will go egg shaped,
: even the factory's told us about this,
: Mercury & OMC. The problem is all the
: engines are set up to run at a set temp.,
: most auto's is 180-200 degrees, the marine
: eng's at 160 degree's, if they have a
: enclosed cooling system, then thay will also
: run around 180 degree's. I would get a 160
: degree thermosat and try it,also, when
: thermosat is marked 160, it will
: "start" to open at 160, it may not
: open 100% untill it gets to 170 or so, I
: have tested many to make sure they work OK.
: Another thing we would find, the water pump
: vanes would wear down, hard to see unless
: you have another pump to look at., just my
: 2-cents, good luck with it, Wayne in sunny
: Fl.
:
:
:
:
: --Previous Message--
: Hey Dan:
: Are you not running a thermostat at all with
: no problems?
: Interesting, I had always understood that
: the thermostat not only keeps the engine hot
: enough but also slows down the coolant flow
: so it has time to cool as it passes through
: the radiator.
: Too fast a coolant flow can also cause the
: engine to overheat.
: Will R
:
: --Previous Message--
: That is good info, so I must have the right
: radiator. Finally found my manual, the 6
: cylinder is 11 quats vs 10 for the 150.
: That extra capacity could be in the engine.
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