Universal diessl overheating

[Salvaduchi]

Hi everyone I have a little problem I have a 3 cylinder universal diessl m-25XPBC 18 HP it's over heating my partner took the boat and he forgot to open the thru hole drove for 20 mins then noticed the motor.was very hot then stopped I replaced the head gasket because there was water in the oil replaced the impeller replaced the water pump I cleaned the heater exchanger I have alot of water coming from the exhaust manifold ireplaced the thermostat and motor is still over heating I don't know what else to do can someone help me with what I can do next thank you very much

 

[shrew]

The fact that you cleaned the heat exchanger tells me you have a closed cooling system. However everything you did is on the raw water side.

1) Is there antifreeze on the closed cooling side?

Over time a heat exchanger will fail if it's lived in saltwater. When it doesn't it develops tiny pin holes in the tubing. The closed cooling side is much higher pressure than the raw water side. This causes the antifreeze to leak from the closed cooling side into the raw water and out the exhaust discharge. Because the leak is small, you don't visually detect the presence of antifreeze in teh raw water discharge, however over time the levels decrease. The raw water side is eventually cooling empty tubes in the heat exchanger and there is no antifreeze being circulated through the block.

If there is no Antifreeze, fill it and run it and check the levels over time. Add as needed. If this is the case, then consider re-building or replacing the heat exchanger.

 

[Scott Danforth]

remember, the exhaust bits are designed for a mix of cooling water and exhaust with a max temperature of about 220 degrees.

the rubber couplers, etc. have a max temperature of 250 f

your exhaust goes to about 1100 degrees without cooling water

you probably cooked the exhaust manifold to the point of failure

 

[Salvaduchi]

remember, the exhaust bits are designed for a mix of cooling water and exhaust with a max temperature of about 220 degrees.

the rubber couplers, etc. have a max temperature of 250 f

your exhaust goes to about 1100 degrees without cooling water

you probably cooked the exhaust manifold to the point of failure

Hi thank you it's fixed a friend of mine gave me a heat exchanger and it looks like it's all good to go no more over heating thank you very much

remember, the exhaust bits are designed for a mix of cooling water and exhaust with a max temperature of about 220 degrees.

the rubber couplers, etc. have a max temperature of 250 f

your exhaust goes to about 1100 degrees without cooling water

you probably cooked the exhaust manifold to the point of failure