DRM

No heat in my cab. Same temp air in blue or red setting - no matter when first starting up or an hour after driving.

Searching other threads, I checked the coolant level in the radiator - full. Overflow is mostly empty though.

Checking the temp guage - it seems to be staying down close to the 140 mark.. this seems kinda low?

I also read about checking the heater lines for heat to see if it might be a core blockage, I'll do that one night this week.

Any other suggesions?

Scramblinman

Check to see that the switch and operating cable are in good working order?

BigBlue

Might be the door. I know on mine if I don't cycle the door every so often during the year, once it gets cold the blower door will stick and won't change until it finally warms up enough and then you can hear it pop into place.

b4wheeler

DRM,

With all that knowledge building Toys, you cant figure out the heater on you Cummins?????

Just joking......

If your temp is not getting above 140*, do you think you might need to block the radiator a little to help bring the temp up..?

When is the right temp to start blocking the radiator..?

fschiola

Check both heater hoses to see if they are about the same temp after it's been running for a while to eliminate the possibility of a blocked heater core as posted above. Don't rule out a vacuum leak keeping the blender door from operating. Also I would think that your thermostat is probably stuck open if you can't get over 140*. Replacing it will probably solve your in cab heat problem as well as making your truck run better.

On edit: I may have told you wrong about the blender door being vacuum acuated, I'm not sure if the were on your year of truck.

DRM

I started it up for the first time in forever this past weekend. After idling for about 10 minutes, the 2 heater hoses that go back into the cab were both warm to the touch. However, the temp guage in the cab never moved.

I just had the thermostat replaced maybe 3 years ago when I first got it - should it go bad that soon?

Forrest Nearing

your blend door isn't actuating

T-Bone

My thermostat looked like this. My cab never got hot.



T-Bone

Dave88LX

Same problem here on my '97. I need to order a new thermostat I guess, even though mine has less than 8K miles on it. I get no temp registering on my gauge either.

blue302stang

If you are not having temps register you need to take a gander at your thermostat.

snowrodeo

hey, now that cold weather is here again, im having the same sort of problem. so i decided to change my thermostat. my question is, do we need any certain thermostat for our trucks? i found one at an online diesel supply place for $7.50. the local shop wants $30.00 for theirs. whats the difference??? (didnt pay attention to particlular brands) what is everyone using/recomended?? brand, price?? where do ya get 'em??

thanks!

Dave88LX

This is the difference -- an Autozone thermostat. Get the Cummins part.

b4wheeler

What's with the rubber boot. I have never seen a thermostat with a rubber boot before?????

infidel

The Cummins stats do the same thing.
I just tear the rubber part off and trash it, doesn't seem to make any difference at all.

Dave88LX

*** did I spend $30 on a Cummins tstat for then. I researched the heck out of it on here and came to the conclusion to not go with anything less than a Cummins replacement...is that wrong? Should I have just gotten an Autzone tstat, ripped off the rubber, saved $20 and called it a day?