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Loss of coolant 496mag

I have twin 496mags. The sensor on the driver side went off the temp hit 190 degrees immediatly shut down the motor. Looked in the engine bay and the there was coolant loss in the bilge. Came in on one engine. Checked the hoses cant find the coolant leak? All hoses and connections seem in order? Could it be the impeller?? I figured i blew a hose or a loose fitting to a hose. No harm done to the engine. Any advice would be appreciated. Thanks

Re: Loss of coolant 496mag

Your coolant is probably coming out of coolant tank pressure cap. Sounds like your lossing coolant capacity cooling on your raw water pump. If you have checked for blockage or debris in the raw water side, sand,etc and its clear then I would supect a problem with your raw water pump. The impeller could be bad but make sure it is replaced with all the proper parts. Some guys have still had overheating problems after impeller replacement because the pump was not completely checked and reworked. Have a shop with the Merc digital reader check the raw water pressure after the pump rebuild to verify its in spec. Hope this helps,
Ray @ Raylar