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md7a 110s low water flow

troutski

New member
Hi All,
New to me mD7a and 110s engine runs well and appears to be well maintained. No smoke, started easily, sali drive seems to function well. Area of concern is what appears to be low volume of cooling water flowing out the back. Had a diver clean out the inlets, didn't appear to be clogged. Possible impeller change out due?

thanks,

mark
 
Impeller is always the first point to start, but you should even check for corrosion/restriction in exhaust outlet.
 
If impeller is replaced and flow is still poor. Remove thermostat housing and check condition of lower port. That is bypass water flow for exhaust. Being cast iron it will corrode and close up, restricting flow.
 
MD7A Remove Thermostat Housing

My MD7A is overheating. Water is coming out the exhaust port, at what seems like an adequate rate, but I have no frame of reference. I installed a new impeller in the water pump, which did not fix the problem. I'm now trying to remove the thermostat housing to install a new thermostat. I've loosened the housing, but it's still held in place by a metal tube that runs from the thermostat housing straight back to the water pump (see attached photos). The connection of that metal tube to the thermostat housing looks like a compression or friction or welded fitting - nothing to get a wrench on. Can the thermostat housing be separated from that metal tube, or does that tube need to be disconnected at the pump housing, and then be removed still attached to the thermostat housing?

Hopefully the thumbnail images below can be viewed larger (new forum member - first time posting).
Hi Vosman - fellow Annapolitan.

Dan
Volvo Thermostat Housing (2) LoRes.jpg
Volvo Thermostat Housing (4) LoRes.jpg
Volvo Thermostat Housing (8) LoRes.jpg
 

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