Volvo Penta MD2020D blocked on freshwater cooling side (I think..)

[corbieres123]

Hello,
I am in the process of redoing/cleaning the wet exhaust and cooling system on a Volvo Penta MD2020D. In the freshwater side of the cooling system, I seem to have a blockage between the opening in the engine block which houses the thermostat (the thermostat and housing have in removed see link 1 part 12) and the exit pipe from the pump housing which returns to the header tank(link 2 part 11). It was very gunked up in there, but if I pour water through the sensor plug hole(link 2 item A or 17) or through another plug hole on the other side of the pump housing (link 2 part 16 I believe, hard to see) water goes through the exit pipe. I have flushed all 3 of these out with hydrochloric acid, but I can’t seem to get any water, acid, or anything else through the opening in the side of the engine block which house the thermostat to come out the exit pipe on the pump housing.

My first question is…. Should I be able to pour water into that opening and have it come out the exit pipe ? I'm sorry that I can't seem to find a drawing of that side of the blockA marine mechanic handed me a drawing of the MD2030D and said there was a thermostat in there and that the whole pump housing had to come off. Clearly there is no sign of a thermostat there on the drawings of the MD2020D.

Any thoughts ?

Thanks !

Link 1 :http://www.marinepartseurope.com/fr/volvo-penta-vueeclatee-7740690-26-4159.aspx

Link 2 :http://www.marinepartseurope.com/fr/volvo-penta-vueeclatee-7740690-26-2434.aspx

 

[tillergirl]

According to the manual:

"Undo the collant hose which comes from the seawter pump, by the rubber housing at the front of the heat exchanger.

Also undo the exhaust hose from the exhaust riser. Make sure that water can not find its way into the boat via the exhaust hose. For safety's sake, lift up the mouth of the hose sohigh that it comes above the waterline.

Under screws 1, 2 and 3 (they are the altenator mounts). Loosen the alternator drive belt by pressing trhe alternator in agains the engine block.

The screws which hold the alternator bracket and electrical distribution box in place also hold the expansion tank/heat exchanger/exhaust pipe. Be careful when you take the screws out, the entire package is now loose and is quite heavy. Do not allow it to fall unchecked since the alternator could be damaged.

The thermostat and the large spring are now loose and can be removed. The large gasket must be removed and replaced by a new one when everything is installed again."

It is not the clearest!. Elsewhere it says: " The thermostat is located between the exhaust pipe and the cylinder block. The exhaust pipe must therefore be removed when the thermostat is to be changed or inspected."

 

[corbieres123]

Hello and thanks for your response.

Sorry that I did not specify that I have already taken everything apart. Header tank and exhaust riser are off, thermostat is out, hoses disconnected!

 

[corbieres123]

I think I've had a late night epiphany..... realized that I have misunderstood in which direction the water flows throw the pump on the freshwater cooling side.

What have been refering to as the exit pipe on the freshwater pump housing(link 2 part 11) is actually the intake pipe. When I am trying to pour water into the engine block where the thermostat was(link 1 part12), I am pour it against the direction of the flow.

Solution(IMO) block up the intake pipe and fill the pump housing with water and see if it comes out the side of the engine block.

Will keep you posted.

 

[graeme ellis]

hi guys I have the same problem with md2020 got salt water through the fresh water side stuffed the themo taken it that out completely as in aus did think needed it motor runs fine with out but no circulation to hot water heater or motor removed fresh water pump no great salt build up so l guess a blockage some where in the block ???

any ideas Graeme