2000 chevy 3500hd 6.5l diesel truck wont warm up ever and after driving and come to a stop or even just lower speeds truck pushes all ALL coolant out of overflow. Went through 8 gallons t o go 80 miles down highway. So in the past month this truck has gotten new water pumo new thermostats new radiator cap im lost at this point please any advice would be great

 

Blown headgasket or cracked head most likely.
Any antifreeze in the motor oil ?

 

Check your oil to see if it looks like chocolate milk. You can also pull the upper rad hose off the engine, and look down in the neck that goes into the block, and see if you have bubbles coming to the top. If you do, you need a headgasket.

 

A friend went through the same trouble,turned out to be a cracked block in #8 cylinder.

6.5 blowing coolant everywhere (Total Rebuild) - Diesel Place : Chevrolet and GMC Diesel Truck Forums

 

he's got a 2000. More likely HG or Head...Atleast I hope so for his sake. If it were a 97...I'd be worried...

 

On a 13 year old truck there is always the chance it has already had a transplant of an unknown vintage?

 

Thanks guys turns out the thermostats I bought a week ago from orileys were bad one was stuck open and other wouldnt open thanks again

 

That should not cause it to push coolant out of the overflow.

 

*2
The open stat should still flow enough coolant to prevent boiling to the extent to cause a geyser.

 

Glad to hear it was the Tstats, I had a similar problem, and yup, it was the Tstats. so simple.... so frustrating