commins engine not heating

[tomta27]

Hi folks,I have a problem with Cummins 6 B5.9 water temp wont excede 45c.I have done the boiling kettle test on termostat and it opens at 65c,
fitted new impeller and checked heat exchanger it was very clean, puzzled at this stage. All replies welcomed and Thanks in advance.

[amarinesurveyor]

Sounds like maybe the thermostat is wide open all the time? If you can check the temperature on the head near the thermostat with an infrared thermometer it would tell you if your gauge is reading properly. Or if you don't have an infrared, you can do it the old fashioned way by sticking a mercury thermometer in the heat exchanger.
The Cummins 6B5.9 should probably be running around 170F to 180F (I think that is about 80C).
Brian

[Chief Engineer]

I would get the infrared gun....I use mine all the time for checking a lot of things on engines/airconditioning systems. Sears/Napa/sell them....Raychem is another brand.

[S/V Antares]

After you check the real temp as the chief and others suggest you may want to check the gauge.

If you have the original control panel it should be fitted with VDO gauges with a temp gauge showing 120 C (250 F) max scale. If someone has used a non VDO sender it may very well read 20-30% low. If the gauge is a VDO unit it will say so on the front. (Lower center, small letters) Check the temp sender. If it is a VDO unit it will have "VDO" stamped on one of the hex flats (Where the wrench goes) If it is a dual station sender it will have a "D" stampted as well. Also the part number inabreaviated form.

Good luck

[GordMay]

Originally Posted by S/V Antares

After you check the real temp as the chief and others suggest you may want to check the gauge...

Dual station senders will read about 1/2 of single station senders.

See' Testing Engine Gauges', and the Sender Resistance Chart, on page 2:
Pg 1:
http://www.cruisersforum.com/gallery...&cutoffdate=-1
Pg 2:
http://www.cruisersforum.com/gallery...&cutoffdate=-1