Volvo penta md2030d coolant loss

Hi everybody.
The other day when cruising on my Bavaria 38C with a 2005 VOLVO PENTA MD2030D diesel engine I got an overheat warning and shut it down immediately. I found the coolant expansion tank empty and added 4.5l of coolant which strangely enough disappeared completely and immediately without leaving any visible or physical trace. I took me hours to return to the marina on sail only. Then I refilled the expansion tank, restarted the engine for a few minutes to enter my berth and it ran smoothly, but afterwards the tank was empty again. I suspected, dismounted and checked the fresh/sea water heat exchanger but found no leaks. The other theoretical possibility would be a blown head gasket, but there is no water in the oil, and a loss of more than 4.5l (1 gallon) of coolant in a few minutes seems a lot to me. Before starting any serious and possibly costly repairs, has anyone any idea where all this coolant has gone...???
Thanks for your attention.

Re: Volvo penta md2030d coolant loss

Put some food dye in the coolant and trace it. You have posted in the Gas/petrol engine section, you might have more replies if you post it in the "Marine diesel engines" section of the forum.

Re: Volvo penta md2030d coolant loss

dypcdiver said:

Put some food dye in the coolant and trace it. You have posted in the Gas/petrol engine section, you might have more replies if you post it in the "Marine diesel engines" section of the forum.

Click to expand...

Thanks. The coolant was dyed anyway.

Volvo penta md2030d coolant loss

Hi everybody.
The other day when cruising on my Bavaria 38C with a 2005 VOLVO PENTA MD2030D diesel engine I got an overheat warning and shut it down immediately. I found the coolant expansion tank empty and added 4.5l (1 gallon) of coolant which strangely enough disappeared completely and immediately without leaving any visible trace in the engine compartment. I took me hours to return to the marina on main sail only. Then I refilled the expansion tank, restarted the engine for a few minutes to enter my berth and it ran smoothly, but afterwards the tank was empty again. I disconnected the exhaust manifold and saw some newly added coolant running down. I suspected, dismounted and checked the fresh/sea water heat exchanger but found no leaks. The other possibility then would be a blown head gasket, but there is no water in the oil, and a loss of more than 4.5l (1 gallon) of coolant in a few minutes with engine not running seems a lot to me. Before starting any serious and possibly costly repairs, has anyone any idea where all this coolant has gone...???
Thanks for your attention.

Re: Volvo penta md2030d coolant loss

Try a radiator pressure tester on the heat exchanger?

Re: Volvo penta md2030d coolant loss

Hi everybody,

Finally I dismounted half of the engine and found a 1/2 inch hole in the aluminum heat exchanger housing near the iron cast exhaust elbow. That solves the mystery but carries a $1000 price tag for an original replacement part (a lot of money if you consider the price tag of a whole refitted engine). Anyway it would be unwise and unsafe to try to repair this as there probably are other corroded places in the housing just waiting to go south as well. The previous owner apparently didn't look well after his engine...
Nevertheless there seems to be no other damage, which is quite fortunate given the circumstances .
Thanks to all of you for your help and attention.