Yanmar 3 gm 30 overheating

[Jacana]

For the first time today after 15 mins of operation engine overheating light and alarm sounded in panel.
Just checked engine and found the coolant in heat exchanger has been emptied out and coolant now in engine bay bilge.Any clues as to why.
Thanks Geoff.

[Wotname]

Yep, you have a leak somewhere
Try hoses and pumps first.

[UNCIVILIZED]

Check all of your hoses for; chafing, holes, splits etc. As well as all of your seals which you can think of... pumps, tanks etc.

Also, prior to refilling your cooling system, check all of your other fluids. Both in terms of level(s), and to make sure that they look okay. You don't want to be firing the engine up if say, there's a crossover leak from one system into another. Thereby contaminating another of the power plant's vital systems.

[Jacana]

Thanks ,found a pinhole in hose ,had to really get the motor loaded to get temp up enough to locate the leak.

[a64pilot]

When things like this happen, you have two choices. Replace the hose and hope, or replace all the hoses and while your there, flush the coolant and put in a new thermostat.