Bukh DV 10 cooling system

[morgandlm]

I know that this has been a popular (frequent?) topic but I could not find a response to match my current issue . I have a raw water cooled 34 year old Bukh DV10 in my Sadler 26 and although noisy and tricky to work on it has been a reliable engine. I am in the process of overhauling the cooling system again and this time will also give the cooling system a chemical flush. On dismantling the thermostat housing I found evidence of black carbon build up just inside the port that goes off to the exhaust injection bend. This indicates to me that presumably on start up, before the water flow becomes established some exhaust pushes its way back into the thermostat. Two years ago I did have an impeller failure that lead to an overheat alarm that I was quickly able to resolve. Might this be when the carbon build occurred or have others found such a problem in an otherwise normal engine? I expected to find lime build up - not carbon. Although the engine does not overheat perhaps the water flow rate is too low as well thus aggravating the problem. Any shared experience will be very welcome.

Finally has anyone found a good way to remove the cooling water injection tube/flange at the front of the engine that is tucked in behind the flywheel. Is there a trick?
Thanks for any advice
David Morgan

 

[Mistroma]

I know that this has been a popular (frequent?) topic but I could not find a response to match my current issue . I have a raw water cooled 34 year old Bukh DV10 in my Sadler 26 and although noisy and tricky to work on it has been a reliable engine. I am in the process of overhauling the cooling system again and this time will also give the cooling system a chemical flush. On dismantling the thermostat housing I found evidence of black carbon build up just inside the port that goes off to the exhaust injection bend. This indicates to me that presumably on start up, before the water flow becomes established some exhaust pushes its way back into the thermostat. Two years ago I did have an impeller failure that lead to an overheat alarm that I was quickly able to resolve. Might this be when the carbon build occurred or have others found such a problem in an otherwise normal engine? I expected to find lime build up - not carbon. Although the engine does not overheat perhaps the water flow rate is too low as well thus aggravating the problem. Any shared experience will be very welcome.

Finally has anyone found a good way to remove the cooling water injection tube/flange at the front of the engine that is tucked in behind the flywheel. Is there a trick?
Thanks for any advice
David Morgan

No idea about the carbon build up, I never noticed this on my old DV20 over 23 years. Unless my memory is playing tricks, the front flange was always easy enough to remove with an ordinary Allen key. I think access is pretty similar on the DV10 and DV20.

The long bolts on the thermostat housing were more of a problem. The engine was 5 years old when I bought the boat and only removed the thermostat when 9-10 years old. I made a point of cleaning them up and using Copper grease. I think I ran across a set in the garage recently, still in good nick. Can't remember if I binned them.

The front plate you mention was prone to a slight water leak, nothing major but I sometimes got salt build-up during the year. I hope the bolts do turn easily.

 

[LittleSister]

I've not removed that cooling pipe at the front of the engine myself, but read that it can be achieved with a cut down allen key (+ the application of plenty of robust swear words and a sufficiency of knuckle skin ).

 

[Poignard]

I've not removed that cooling pipe at the front of the engine myself, but read that it can be achieved with a cut down allen key (+ the application of plenty of robust swear words and a sufficiency of knuckle skin ).

Yes , the cut down hex key is the key to it!

Last time I had mine off I thought it would be easier if I fitted hex headed screws. I can't remember why I didn't. Perhaps I forgot, or there may have been some other objection to it.