I have an 06 5.9 auto. Every morning that its cold I start my truck and let it run for about 15 minutes with defrost on full blast, heat on full blast. That way when I run carpool my three kids aren't so cold.

This morning the outside temp was 27 degrees. Did my normal routine, but when I went out to get in the truck it was like I had never turned the heat on. As I started to drive, the temp gauge started rising, but still no heat. After about 4 miles the temp gauge shot up to the red, and my check gauges light came on. Then the temp gauge went down to normal and the heat finally kicked in.

Anybody have a clue what is going on? Thanks in advance for any help.

I did post this in the 2003-2007 area, but I am just trying to get an answer.

 

Sounds like you need a new thermostat.
Buy one from Cummins, the generic auto parts one sometimes leave much to be desired.

Replacement is very easy.

 

I'm with Infidel, try a new tstat!

 

When you buy a new thermostat, ONLY buy one from Cummins. The others are not that great and the temperature swings all over the place.

 

Why don't you just have the truck plugged in 1-2 hrs before leaving (timer). You will have warm air when starting and won't need to run the truck for 15 minutes. My truck is in the garage and I still plug it in when temperatures are below 40* F just for the inside heat. Just a thought.
Us yankees in upper Illinois haven't seen 27* for a while, consider yourself lucky 18* F for the high today geeeeeez.

 

I would love to plug it in, but I do not have an engine block heater.

 

You should have the heater, just need the cord.

 

Well I hope it’s the thermostat, but something doesn’t make sense. The heater pulls coolant from before the thermostat, so the heat should have worked. The only time I have ever had anything like this is when the coolant was frozen in the block. But 27 degs doesn’t seem like it would cause a problem.


Joe

 

I found mine thanks to this link. http://wiki.dieseltruckresource.com/...y_Block_Heater

 

s'port diesel you do have a heater in the Cummins, just missing the chord. Bark has a link and here is a picture of where it is. On yours there is probably a cover on it. The cover screws off and you can get a chord from a dealer, I got my chord from Napa. BTW, I hope it just a thermostat too but it sounds more like sr4440 says, have your antifreeze checked.

 

Any chance it's a broken heater door?

 

Not with the temp gauge in the red zone!

 

First thing you need to do is verify that your coolant is at the proper level in the radiator.

 

Ok, I added coolant last night, it was low and has seemed to fix the problem. Thank you all for the input. Now, on to the link about adding an engine block heater.....

 

Now you need to figure out why it was low...lol