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Late model raw-water engine, Westerbeke style thermostat, and a new bronze thermostat housing just installed. Thermostat has one large spring as opposed to three of the old style, rated 140 degree, not the Volvo style in the spacer kit.
The engine had been overcooling for some time. Did an acid flush to clean out the oily residue in the cooling passages, cleaned the thermostat, and installed the new housing. The old housing had the middle boss or tube that the thermostat seals against corrode away. Thought this was the cause of my overcooling problem. I did the acid flush with the old housing and the thermostat removed and installed the new housing.
Got up to 120 on the first test start at the dock, but took it for a test spin and it didn't get up to 120 again until I was almost at full throttle. I shut off and coasted for a bit, then restarted and the water temp had risen a bit as the block heated the sitting water, but promptly fell as water circulated again. At idle speed and lower throttle settings, it wasn't above 100. Back at the dock I could feel the thermostat housing cooling rapidly as the engine was started and ran.
If the thermostat doesn't open to seal off the boss and force water through the block, I'd expect the housing to be cool as water bypasses to the manifold, but why then does the temp not increase? Is water always circulating through the thermostat housing?
What path does water take through the engine when the thermostat is open (pressing up against the housing boss) or closed (in the down position?)
I'm trying to understand what happens when the thermostat fails.
Thanks for any input you can shed on this.
Micah
The engine had been overcooling for some time. Did an acid flush to clean out the oily residue in the cooling passages, cleaned the thermostat, and installed the new housing. The old housing had the middle boss or tube that the thermostat seals against corrode away. Thought this was the cause of my overcooling problem. I did the acid flush with the old housing and the thermostat removed and installed the new housing.
Got up to 120 on the first test start at the dock, but took it for a test spin and it didn't get up to 120 again until I was almost at full throttle. I shut off and coasted for a bit, then restarted and the water temp had risen a bit as the block heated the sitting water, but promptly fell as water circulated again. At idle speed and lower throttle settings, it wasn't above 100. Back at the dock I could feel the thermostat housing cooling rapidly as the engine was started and ran.
If the thermostat doesn't open to seal off the boss and force water through the block, I'd expect the housing to be cool as water bypasses to the manifold, but why then does the temp not increase? Is water always circulating through the thermostat housing?
What path does water take through the engine when the thermostat is open (pressing up against the housing boss) or closed (in the down position?)
I'm trying to understand what happens when the thermostat fails.
Thanks for any input you can shed on this.
Micah