Volvo MD7A Thermostat

[simpsoned]

Have an older MD7A and it never comes up to temperature. Suspect the t'stat is frozen in the open position or the previous owner decided he didn't need one. Looked on line and the cost for the t'stat is outrageous. Does anyone have information on a replacement t'stat that will work that I can pick up at a local auto parts house?

Also, what damage can result from running an engine on too low an operating temperature?
thanks
Ed
Newport 30

 

[kloudie1]

simpsoned.. what is the actual engine running temperature? Is the gauge correct? Is the engine fresh water cooled or sea water cooled?
Running at too low a temperature can cause a lot of wear and corrosion because the oil will not get hot enough to cook out the moisture and stuff..

 

[simpsoned]

thanks for the questions, Claude...the actual running temperature is just enough to lift the needle off the bottom of the temperature gauge..and yes, the sensor and gauge are correct...I pulled the sensor and put it into some 160 degree water and the gauge read about 1/4 scale level. Since the original t'stat is set for 60 degrees C opening temp (roughly 160 degrees F), I used this as a start point for how hot the engine should run. We are in fresh water, boat has never been in salt water...Last time I had the engine running for a prolonged period (about 1/2 hour) the temp never got to 1/4 scale.

 

[kloudie1]

Ahhh Haaa .. looks from the parts list that I found on the net that your engine is raw watter cooled and has no heat exchanger.. Sounds like you've got the diagnosis correct .. your thermostat sounds to be stuck open a tad.. I am not familiar with that engine so I can't tell if a "normal" automobile thermostat is what ya have.. On the Yanmars, it is very different and only available through the friendly Yanmar folks for about 4 times what a regular thermostat costs.. I wouldn't be surprised if Volvo did the same thing.. Good Luck with them.. I see that teh price is around $100 for the thermostat kit.. but the drawing looks like a normal thermostat.. I would pull it and take it to an auto parts place and see what they can do for ya..

 

[simpsoned]

I went to my local NAPA parts house and they dragged out their marine engine catalog. Lo and behold, in the Volvo Penta section is a list of about 6 different t'stats for the engine, with a cross reference to the original Volvo part number...cost $1759 plus shipping from their warehouse...total of $26.00... I now understand why folks say Volvo is Norwegian for Gold.