Sooo.....ive replaced radiator cap, thermostat, temp sensor, water pump and burped the coolant after I flushed everything also had a head gasket test done ...heat wont work until It starts to over heat then I remove cap, temp gauges falls to normal in blink of an eye and heat starts workin..truck is running kinda rough no codes...no check engine light....no oil and coolamt mix no white smoke WTMF IS GOING ON!!!!!!!!!!!!!!!

 

Was it acting the exact same before you replaced the thermostat? If it is overheating, I would think you either have a stuck thermostat, air bubble in the cooling system, or a had gasket issue. Sounds like you had the head gasket eliminated. Maybe the new thermostat is sticking closed? Maybe you should try using a funnel like this to make sure the cooling system if full.

http://www.summitracing.com/parts/li...FYMjgQodzDsASw

 

It all started then thats when I started replacing things new cap, acted the same, new thermo, still same new pump and sensor still nuthin im lost

 

And as far as the funnel when I readded coolant I cut a coke bottle and used to burp it

 

I agree with Roadie...that the new T Stat is probably sticking. and that maybe still have that last bubble to burb out of it. What brand of T stat did you put in?? If it was a cheaper one...then maybe that's the issue. Also did you change the Serpentine belt too with all the other stuff?

 

I did not change belt belt appears good everything spins great ... the top hose collapsed today when doin another coolant test for exhaust in coolant..... and the guy thinks its a radiator clogged up.....I wouldnt say the t-stat was expensive but its not a lower end I belive it was from bumper to bumper because the autozone stats dont actually fit

 

I think the hose collapse is indicative of a bad radiator cap. It's supposed to let coolant flow back into the system from the overflow bottle when it cools down. It the cap doesn't allow the flow the hose will collapse because as the coolant cools, it shrinks and causes a vacuum.

 

I'd think its a block issue. Some where the flow is being stopped.

 

Its d9es it without the NEW radiator cap on aswell

 

It could be that the upper hose is disintegrating from the inside out too. It is rare these days, but I did run across it before. unless there is a spring inside.

Did you note what the lower hose was doing too during the time when the upper radiator hose was collapsing? Or either of the heater core hoses? Were the any of the hose replaced recently?

 

Remove the thermostat. See what it does then.

 

Just a question, because I'm confused. If there's a stuck thermostat and the coolant is REALLY overheating, how can he remove the radiator cap without having a geyser?

And, if somehow the radiator is still cold and nothing boils over, why does removing the cap fix everything right away?

To the OP, when your system is saying that it's overheating, is there pressure in it? Can you squeeze the upper radiator hose at all, and is it hot?

- Jack

 

Yes it has pressure , I just back it off a little to slightly realease pressure (as you would do with a coke thats been shook) and I thought I had it all fixed drove for a day acted fine then the next day started idling rough but no codes, had some coolant spray out the radiator cap.....its holding pressure over night, today its been running fine again

 

some thermostats can be buggered right out of the box. if it was dropped at the store or warehouse, it can rupture the thing right quick. if the rad hose is collapsing while its running, there is no flow. so a closed T stat or plugged rad is suspect

 

Did you change your serpentine belt recently? I have seen somebody run the belt where the water pump was running backwards. I know, sounds crazy but he didn't route it correctly. Worth a shot.