My engine suddenly overheated and it has lost engine coolant from the heat exchanger. What do I check to fix it?
The loss of engine coolant is probably caused by a leak, although if your catch tank was empty before then the engine may just have overheated without losing coolant. Fill the system with water (you don’t need antifreeze until the engine is repaired) and pressure test with an automotive radiator tester (ie it pressurizes the system to force air/water out the leak). The usual cause of loss of coolant is a failed engine coolant pump (the engine coolant pump on diesel engines is driven by the alternator belt, and the pump has a hole in the bottom which is designed to drip water when the seal fails so it can be checked quickly to see if is leaking) or hose or a leaking heat exchanger (if you haven’t replaced the zinc in the heat exchanger regularly then the heat exchanger could have corroded inside and is leaking coolant into the sea water, and so you won’t find an external leak on the engine.. you’ll have to remove the heat exchanger and have it rebuilt at an automotive radiator shop The
