Volvo penta MD 11 D

[Gotcha]

My second hand pretorien is equiped with a volvo penta MD 11 D. Once the engine is warm, the temperature gauge starts swinging till just touching the red sector, and then at once collapses back until almost entirely cold. Hereafter the cycle starts again. The cooling channels are not obstructed, neither are the cooling channels around the exhaust. Also, I have already changed the thermostat and the impeller. What can be wrong, or is this normal?

 

[bedouin]

I don't know if it's normal, but I get exactly the same symptoms sometimes with my MD2B

 

[maxi]

Have a look at the seawater inlet hose (between seacock & seawater pump), these have the nasty habit of deforming or self-closing when using moderate or high revs, and returning to normal when the engine is on tickover or stopped.
Bends in the hose can bring this about or, breakdown of the inner lining of the hose, either way it's difficult to detect.
A few euros (pah!) spent on a new bit of hose may well solve your problem
Good luck.

 

[Aeolus_IV]

I'd be worried by this swinging temperature - have you had a look at the thermostat itself? It was our ignorance combined with this type of fault which brought our old MD2B to an end. Now have nice new 3GM30F instead, but expensive option if it can be avoided.

Another Wauquiez - nice boat, but then I would say that.

Jeff.

 

[Johnjo]

Have you fitted a new themostat recently? had the same problems you
describe on a MD2B that i had,
The suppliers had sent me the wrong thermostat, I have read that they did
this to several other people!!
got the correct one and no more problems.
mike

 

[Aja]

Have you checked the temperature sensor?

It may be that it is just faulty

Donald

 

[chrisD]

I had a similar problem with an MD11C, except that it would go right into the red sometimes, and the water outflow then ceased. Then it would swing back again and the outflow would restart.

After several replacement thermostats, cleaning out the channels etc, and spending a lot of money, the problem turned out to be that the lining inside the exhaust hose had completely collapsed. Not very expensive at all once we knew what the problem was, and now the temp remains very steady.