[LapeerLandscape]

2004 gmc 4500 6.6 duramax with no heat. I just run it for about 45 minutes and the temp never moved until I got within 1/2 mile back to my yard and the temp gauge goes all the way to the red and then back to just below normal and no heat out of the heater until that point. My first thought is thermostat but it has 2 and whats the chance of them both going bad. This has been going on for a little while and it has been going through anti freeze and doesnt seem to be leaking it.

 

[Ajlawn1]

Air pocket...? I think there is a bleeder if I remember...

 

[gcbailey]

check your coolant level.... We've got an '04 3500 and if the coolant gets the least bit low, no heat unless it's on full blast.

 

[LapeerLandscape]

Air pocket...? I think there is a bleeder if I remember...

Thats what it acts like but wouldnt the engine/temp gauge still get hot.

 

[LapeerLandscape]

check your coolant level.... We've got an '04 3500 and if the coolant gets the least bit low, no heat unless it's on full blast.

Topped it off this morning to salt and still put 3/4 gallon in it tonight.

 

[1olddogtwo]

Head gasket(s).

 

[LapeerLandscape]

Head gasket(s).

I think thats the anti freeze issue but would that cause no heat and nothing to register on the temp gauge?

 

[1olddogtwo]

https://www.littlepowershop.com/how...duramax-head-gaskets-and-what-to-do-about-it/

I don't know the 6.6 but head gaskets come to mind.

 

[Randall Ave]

Replace the therms first, It has two, but they are NOT the same, make sure you put them in the correct holes. I have remove duel Cat therms and seen both of them broken.

 

[Hydromaster]

The coolant is either going out the talepipe and/or in the oil,

Q If you removed your oil fill cap What does it look like on the underside

 

[Randall Ave]

If there is no fluid against the sensor, sometime they will not read correctly.

 

[LapeerLandscape]

https://www.littlepowershop.com/how...duramax-head-gaskets-and-what-to-do-about-it/

I don't know the 6.6 but head gaskets come to mind.

Thanks Pat that was helpful.

 

[LapeerLandscape]

The coolant is either going out the talepipe and/or in the oil,

Q If you removed your oil fill cap What does it look like on the underside

Its not getting in the oil, more than likely head gaskets.

 

[1olddogtwo]

I hope that isn't the case, t-stat cheaper

 

[Ajlawn1]

I put one of these in an old loader before might be an option for ya....

 

[LapeerLandscape]

I hope that isn't the case, t-stat cheaper

With the anti freeze loss I'm pretty sure its the gaskets after reading the article I just wasnt sure how the no reading on the temp gauge tied into it. I'm not big on snake oil type product but we tried some K-seal as I had heard good things about it but it didnt seem to work.

 

[LapeerLandscape]

I put one of these in an old loader before might be an option for ya....

View attachment 188968

Its are primary salt truck that my son usually runs, he can suffer. We need to get it fixed but it will have to wait till I fix the other sreader that I broke Saturday. Broke the output shaft from the gear box, maybe I will take a ic of it. Good thing is we have a spare.

 

[Brndnstffrd]

I put one of these in an old loader before might be an option for ya....

View attachment 188968

The 12v harbor freight heater/defrosters are $8 with a coupon

 

[Randall Ave]

With the anti freeze loss I'm pretty sure its the gaskets after reading the article I just wasnt sure how the no reading on the temp gauge tied into it. I'm not big on snake oil type product but we tried some K-seal as I had heard good things about it but it didnt seem to work.

Do you have a cooling system pressure tester? If yes, fill with coolant, put on the tester and run the engine at high RPM, see what you get. If it jumps up high right away, points to a head gasket.

 

[LapeerLandscape]

Do you have a cooling system pressure tester? If yes, fill with coolant, put on the tester and run the engine at high RPM, see what you get. If it jumps up high right away, points to a head gasket.

Yes I have one, will have to get the adapter for the plastic reservoir. Thanks