Mercruiser 470 Overheating


Old 07-05-00, 01:42 PM
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I have a Mercruiser 470 that is running hot. Have changed the thermostat, installed new sea water pump impeller, removed and cleaned heat exchanger and checked all hoses for obstructions and other damage. Cooling water flow appears sufficient and engine runs good. Runs about 190 at idle and will get to 225 quickly under throttle. HELP?
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Old 07-05-00, 08:38 PM
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Join Date: Dec 1999
Location: Los angeles
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You should look to the exhaust elbow for obstruction first. It will plug up with rust and scale reducing the water flow.
Next will be to check for the head gasket leaking combustion into the coolant.
Is it losing coolant, bubbling out the cap?
are there any leaks at the camshaft seal/water pump?
coolant dripping from the weep hole at the front right side of the block?

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