Put antifreeze in my truck the night before It got real cold. apparantly I didnt let it run long enough to mix right and something still froze up. Heater doesnt work, Thermostat goes hard over to the right then comes back about 3/4 of the way and bounces back and forth from there. Nothing leaking. Oil Psi normal and truck isnt actually getting as hot as it reads. No heat.

I put it in a friends garage for a night with a space heater and a light under the hood. put the correct mix of antifreeze ec in it andI have beeen driving it for days. Still no heat, still overheating.

Changed the thermostat even. Nothing..

Any ideas? Something still frozen in there in the heater core maybe? i am going to throw a space heater in the cab when i get my hands on one, we do not have a garage and its been about 27 degrees day, 4-10 night. So its going to be a ling time until I can just let it thaw and figure out if I broke something.
unfortunately i need it every day, so i have just been driving it and watching the oil psi. So far so good, nothing leaking nothing boiling out etc,.

 

Burp the cooling system. An air bubble will give you those same symptoms.

 

There are a few things that come to mind for mew. First off, doing the repairs in the cold sucks - I live in Iowa so I feel your pain there. Now, there could be air in the coolant system. There are sticky threads on how to bleed it & that would cost you nothing. Your heater core could be clogged, but that would not usually cause the truck to overheat. The water pump is designed to bypass that to an extent. If you are completely certain the radiator is not frozen, look for air & bleeding it out. Keep in mind that if your water pump was already kinda weak, this could have put it over the edge. Look at the weep hole for a trail & listen for pump bearing noise.

 

like the others said, it sounds like you have air in your system, open your radiator cap, and let the truck idle for a while. make sure your overflow tank is filled to the correct level. also did you use premixed antifreeze or concentrate then added water? if u mixed it yourself did you mix before you put it in your truck? because your not supposed to use the water pump to mix your coolant. it doesn't usually mix right away then causes to motor to freeze in cold temperature and can cause rust to form from the inside out. as long as you let the truck run long enough though this won't be a problem (just to mix the concentrate antifreeze and water(if thats how you put it in)) Once you burp your system your heat should blow again and truck won't overheat

 

no air. Wasnt any air in it before it got cold. And thats when the overheating started. Let it run , fill , cool down, run fill, cool down for over an hour just in case. that was my first suspicion.

I think he may be right about the water pump. its just so cold the fluid could be weeping so little its not making to the ground.

If it was the pump, we are assuming its not turning at all right? so the heat is forcing coolant around in there? I know the radiator is fine because it takes coolant and its hot stuff. So if the pump wasnt turning that would make perfect sense

 

The pump could be bad yes, but it would likely make some noise like a sqweeling belt or bad bearing noise before it stop turning completely. When you say there was no air in it before it got cold, does than mean you think there was no air in it or you already did the standard steps to bleed out the air that always gets in when you do something major in the cooling system? If there is a large enough air pocket, it could be forcing coolant out the reservoir overflow right to the ground, likely when you are driving. I hate to beat the air thing to death, but it would be prudent to go through the standard steps to bleed it again before throwing parts at it that may not be needed. If time & money are on your side, then get the pump. If you do, you will still need to bleed the air out because it will be in there.

 

Are your heater hoses getting hot?

 

when it got cold and froze up a bit that night the water pump died. The two things happening at the same time by coincidence jsut had me focused on the wrong things rather than checking the obvious things first...Went out and opened the radiator cap right after my first couple of posts. I feel a bit stupid I did not try this earlier.... This truck has 260k miles on it and apparently the person that did the rebuild saved money where ever he could. The waterpump is OEM!!! What kind of person puts an oversized cam, flat top pistons and different ratio roller rockers into a rebuilt 5.9L and doesn't do the waterpump!!

Anyway, cap off, reved motor, nothing moved. Pulled the belt off and the pully was fine, not a sound. The impeller had sheared itself from the shaft on the inside. Still had a bit of rough metal that was letting it grab at high RPMs so I was getting some fluid movement but not much. got the new pump in this afternoon and spent an hour installing it. Now All is well

 

Make sure you burp the system. Raise the front right corner of truck like on a ramp. This is the only way to make sure you get all of the air out.

 

Glad you got it fixed man! Hows about we find the previous owner & glare at him for doing a **** poor job?