I just replaced a head gasket on a c-3500 5.7 . Had a blast getting it all back together and started up fine once oil pressure built up.Had a little burn off for 15 minutes took it for a spin on a 10 mile test run.Did great first 9 miles and temp started running in the 250'S. Found that the upper radiator house has no coolant running through it.Let her run a bit, got the temp up to 210 and pulled the upper hose off the radiator while she was still running,No coolant...Flushed the coolant system 3 times still can't find the block...This one has me puzzled boys!!!!

 

Thermostat

 

Tested thermostat, 3 different ones,all open up at 195 degrees

 

I think you just missed burping all the air out and your pump went dry. Best way is to shut it off, "ease" the pressure off of the system, and fill it up carefully while the TStat is open. That'll allow the Coolant to flow and fill better. Might have to do this (run/shut off) a couple times to get it filled back up.

IF it had been a bad Stat, you would have still had Coolant in the upper hose IF there had been enough in the system to start with.
Be sure to run (all) your Heaters full blast while you're filling. Also, all this should be done in the Shop/Driveway. Only thing a "test drive" might do, is strand you out somewhere, where you can't do anything about it.

PS:
A lot of people miss this very obvious point, that being...
Find out how much Coolant your ride holds. Mix that up, and if you can't put it ALL in the system, something's wrong !

 

Thanks swhouston and kevinkpk, got her running great....there was a lot of gunk built up and clogged tstat and upper hose.....running as good as new....

 

You said you flushed the system 3 times, and you still had "gunk" in it...WOW !

I can't help but think your problems aren't over. How'd you "flush" the system ?
Given what you said, I bet there's a lot of gunk in your Heater Cores, did you back flush them ?

 

This truck has been sitting for over a year. When I asked about the truck they said the water pump leaked and once they got tired of adding water to it everyday they parked it.So I asked if I could take a look at it and see if I could fix it they decided to let me.It turns out the water pump was fine but the radiator had a crack in it.I replaced the radiator, t stat,hoses oil change , plugs , wires and set the timing back in June ran great until 2 months ago.The ranch hand said it has been leaking coolant but they didn't think anything of it, they just added a half a gallon water to it every hour and continue to use it.I rushed over there and it was to late , they cracked her heads.They cracked her heads back in October and still ran it like that,I have been pulling gunk out of her since I replaced the heads.The heater core works but it is shot as well.

 

OH ok, I understand now. So is this just a project you're doing for someone, or did you buy it ? Restores like that, can be a lot of fun !

 

It's turned into a project,I hated seeing this 94 one ton just sit there like that.I brought life back to this beast although I find myself hesitant to give her back, all good things must come to an end...

 

HA, I know what you mean !

Stuff like that is like old Dogs, they may have Fleas, but ya love um anyway.

You thought about just buying it ?