I have a 1997 Volvo/Penta 4.3L V6. Does anyone have a diagram of how the water circulates thru this engine. It has a raw water cooling system. Also it has a thermostat built into the thermostat housing on top of the intake manifold appears to control the flow the the exhaust system. What temp would that open at I took the housing off and put it into a pan and heated the water and it opened at 175. That is the temp the engine is running at now. It has run much cooler before , in the neighborhood of 140 to 150 at cruise and 175 at higher than 3000 rpm, It started overheating so I changed the impeller. That didn't help so I took the thermostat housing off and found the raw water neck full of old impeller pieces. And now the temp goes to 175 with no engine thermostat and sits no matter what rpm I am running Thinking maybe the exhaust thermostat was stuck open with some of the old impeller and now I actually have it working correctly. I have checked all other areas for blockage by pulling the water pump off te engine and running water from every direction All flows great. Didnt open the exhaust manifold and check them because when engine is running at idle on the muffs. They are as cool as is the engine wasn't even running but the engine warms up to about 160 or so. Does all this sound normal. I have never allowed the engine to get hotter than about 190. Even when it was what I called Overheating. It runs great just leary of the 175 constant temp. All help is appreciated.
