Truck over heats explodes big hose underneath, but radiator fluid stays cold.
1. New thermostat
2. Head shaved and replaced.
3. New water pump

....any help on where to look would be greatly appreciated!

 

In the thread title you say its a 2000 but in your signature you say its a 1996.
Which is it?
Makes a huge difference.

 

Oh, sorry, I have two.

 

Thats better...

There have been a string of bad thermostats going around, where did you get yours from?

 

Not sure, ill have to check? Where have the bad ones been coming from?

 

I have heard of at least 3 people getting bad one from AtlanticBritish.
These problems are always tough, if the coolant is circulating properly the radiator should be hot.
But you say the coolant is hot, lower radiator hose explodes and the radiator is cold.
So that must mean a water pump that is turning backwards or the coolant is building up excessive pressure on the "cold" side of the radiator.
Either from a cracked block or head, bad head gasket or some other reason that I cant think of.

 

Hmmm? How would the water pump be backwards? That one baffles me. Can it be checked by me?

 

or for that matter, how would I go about seeing if the block was cracked, or not?

 

Improper serpentine belt routing.

He didn't mean the pump is backwards. He meant that it is being SPUN backwards.