Truck is running hot and can't figure out why
 

So my 2000 Silverado is running hot, replaced radiator 8 months ago, replaced water pump today, replaced all heater and water hoses and still gets hot don't know why, checked oil and it's clean, not milky like signs of a blown head gasket, it will run about 10-15 minutes and it will get up to 260 temp. It has fan shroud and every thing stock and can't figure out what's going on

Re: Truck is running hot and can't figure out why
 

It's blowing the water out through the water tank reservoir, thru the hose

Re: Truck is running hot and can't figure out why
 

Thermostat?

Re: Truck is running hot and can't figure out why
 

I've changed it out already

Re: Truck is running hot and can't figure out why
 

what temp is the coolant actually? Is the gauge reading right? The stepper motor in the gauge could be off. A scan tool might be of some help

Re: Truck is running hot and can't figure out why
 

Pressure test the cooling system. Just because the oil is O.K. doesn't mean that the head gasket is O.K., only that it didn't blow into the oil system. Look for a cracked head or block.
What engine do you have? Early 4.8 had a porosity/crapulence issue with the Castech heads. Don't know if 5.3 uses same head.