TMD40A cooling water disappears

[Nunuwawa]

Hello all



I had one engine TMD40A which was overheating, turned out that the cylinder head had cracks so

after a long search we could find a used cylinder head which was totally overhauled pressure test for cracks etc.

What happens now is that after a while using the temperature goes up and alarm, however when measuring the temperature

from the cylinder head it is only 70 degrees C ???

I can add around 4 liters of water keep the overflow tank high and then the temperature goes back to normal for an hour or so, looks like some water disappears……

Anyone any idea?



Thanks a lot



Walter

 

[Leighb]

Maybe post in the Mobo forum, lots of folk on there with experience of these engines who may be able to help.

 

[billskip]

Hello all



I had one engine TMD40A which was overheating, turned out that the cylinder head had cracks so

after a long search we could find a used cylinder head which was totally overhauled pressure test for cracks etc.

What happens now is that after a while using the temperature goes up and alarm, however when measuring the temperature

from the cylinder head it is only 70 degrees C ???

I can add around 4 liters of water keep the overflow tank high and then the temperature goes back to normal for an hour or so, looks like some water disappears……

Anyone any idea?



Thanks a lot



Walter

It is a lot..as said by Leighb, post in mobo forum, lots of knowledge there.
My guess first instinct would be head gasket, others on mobo forum would have good suggestions how to test for faults on your engine

 

[Nunuwawa]

Thank you all

but were do I find this mobo forum?

Thanks

Walter

 

[Plum]

Hello all



I had one engine TMD40A which was overheating, turned out that the cylinder head had cracks so

after a long search we could find a used cylinder head which was totally overhauled pressure test for cracks etc.

What happens now is that after a while using the temperature goes up and alarm, however when measuring the temperature

from the cylinder head it is only 70 degrees C ???

I can add around 4 liters of water keep the overflow tank high and then the temperature goes back to normal for an hour or so, looks like some water disappears……

Anyone any idea?



Thanks a lot



Walter

Suggest you make or buy a coolant pressure tester to find the coolant leak.

How are you measuring the cylinder head temp and why are you concerned about 70 degrees? What temperature do you normally record at that location?

Www.solocoastalsailing.co.uk

 

[oldgit]

Do you have the square heat exchanger ?
The internal brass matrix inside has a habit of failing with age.
IF... it is the matrix, your water/antifreeze could be mixing with the raw cooling water.
Matrix from VP is eyewateringly expensive, did manage to repair mine a couple of times , before there was no longer much material left to solder and had to buy a new matrix.

 

[Nunuwawa]

Thank you for your answer
Yes, it is a matrix
How did you manage to take it out without damaging?
the inlet and outlet or corroded in the aluminium
Walter

 

[colind3782]

Thank you all

but were do I find this mobo forum?

Thanks

Walter

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