Thermostat Problem???

KeepRollin · Mar 25, 2006

I have a Sterling with a CAT 3126. My driver said it seems to be running below normal temperature. It only gets up to around 180 on the road and about 120 while idling. To me it sounds like the thermostat is stuck open. Is this correct, or is it something else?
Thanks
Todd

rode2rouen · Mar 25, 2006

If the engine has a 180 degree thermostat, I would say that everything is fine. You ought to call your dealer and find out what the opening temp of the thermostat is supposed to be.

Also, a diesel engine will usually cool down considerably when idling.

Rex

Larry · Mar 25, 2006

Did you recently replace your radiator?

KeepRollin · Mar 26, 2006

I have not replaced the radiator or anything in the cooling system.
My driver said it does not heat up as warm as it was a few weeks ago.

I will call the dealer and get the info for which thermostat it should have.

Thanks
Todd

simon says · Mar 26, 2006

Your first responder is probably correct. It doesn't sound like you have a problem at all. He should idle that engine at 900-1000 for overnight, or it will not hold temp. and easily cool down to 120.
You will have a problem if the temp. only goes to 150 while at highway speeds: then thermo. is stuck open. You will lose fuel efficiency, but not power...
With A/C on, climbing hills, with load on truck, that engine will easily rise up to 200 degrees with the fan (unless viscous) kicking in before that.

davekc · Mar 26, 2006

I would also have them check fan sensor. Your fan may be running thus dropping the temp. quicker. Had this problem several years ago on a cummins.

Davekc
owner
21 years
PantherII
EO moderator

bryan · Mar 27, 2006

HI
Have him remove the fill cap and idle up the engine then squeeze the top rad hose.If this fixes it then you just had some air in the system.Might not be it, but it is a totally free fix if it does.My 7.3 was doing the same thing last night and thats what the problem was.

Broompilot · Mar 28, 2006

Take it in, mine did this last year. Problem, poor reading from sensor, wire was not grounded all the way causing an incorrect reading. Took 6 attempts to discover cause, the bracket was cracked that the wire was grounded to so thats why the repairs were not working.

Just my luck back to the shop AGAIN time, fuel and $ waisted.

PS this really has been one of two repairs performed on the Cummins.