Temp too low on 55HP Volvo

[Boaterbob]

Volvo specs say thermostat begins opening at 180F. My 55HP sailboat engine under load runs at 140F. Replaced thermostat and got it to run at 150F under load, no higher. I clamped hoses feeding external diesel heat via exchanger and temp went up to 160F. measured with IR various spots. Output of circulator hoses seems cool at 110F. Top external heater exchanger temp is 115F. Circulating heater fluid temp 90 (need 130)

Old thermostat in hot water starts showing opening at 160 and is fully open at 180F. I want higher temp to meet engine specs and to heat boat via exchanger and as of now it will not heat enough to use hydronic heater units which need 110F to turn on.

No "higher temp" thermostat available from volvo. (true?). I do not understand why I cannot get my temp up to spec of 185F at 3/4 load at dock after 45 minutes. Ideas or suggestions?

[chris95040]

What is the temperature of your engine coolant?

Edit, I see its 140F. How are you getting that reading, and are you sure its accurate?

Are you sure you have the right thermostat- I recall other manufacturers would sell a lower temp one for raw water cooled engines, for whatever reason I guess you need to run them cooler when cooling with salt water.

Also, on the bright side, a few of my friends with volvos have chronic overheating, I think i'd rather have your problem.

Are you sure water is circulating through all the passages properly? Sometimes this can manifest as cooler temps in one spot while the rest of the engine silently overheats.

If you remove your add-on heat sinks from the loop and still aren't getting beyond 150 despite a thermostat that doesn't open til 160, I'd say something fishy is going on.

[DougR]

Which model D2-55 do you have? The original model D2-55 A had a cool running problem which was corrected in later models. For the original "A" model there was a service fix that entailed modifying passages in the heat exchanger tank to alter the bypass flow and raise the water temp.

DougR

[Cotemar]

It may take longer to get upto engine temp if you have a hot water heater hooked to the engine.

On Catamarans with 2 VP D2-55 engines, one will always seem to be running cooler, because of the hot water heater taking all the heat.

[Boaterbob]

Thanks for responses. DougR has hit gold with factory issue that is know, but not to my mechanics here in Olympia. I eliminated the "hot water taking heat" possibility by clamping off that circulation and it was still under temp. Apparently this is a known problem but is old enough that my engine needs the fix. It is a 2003 in a Bavaria 41made in 2004.


Thanks for esoteric knowledge!!! I will inform the local diesel boys who care.