coolant running into over flow tank

[ADV]

I am having a problem where some time when I first start the truck and let it idle to warm up it pukes coolant into the overflow tank.

I was thinking a possible sticky thermostat because the temp will get up to 220 and I will have no heat from the vents. Then it will suddenly jump to 190 I will have instant heat. It will sit at 190 all day after it drops to 190.

I just replaced the thermostat with a motocraft one. Also new radiator, heater core, coolant filter, and new fleet charge coolant. Water pump about 1 year old.

Do I possibly have a faulty thermostat?

 

[Black dawg]

you have trapped air in cooling system. t stat opening is delayed because of air...no heat because of air in heater core.

pull off a heater hose at the core, and try getting more coolant in the radiator.

 

[Hydro-idi]

^^^Agreed. Sounds like an air pocket to me. Sometimes it takes more time than one would think to bleed all the air out of the cooling system.

 

[stealth13777]

Third vote for air. Could open your rad cap too while warming it up (not driving). Least that's worked for me with gassers

 

[IDIoit]

someone posted a modified coolant pressure tester that would suck all of the air out, i think it was Towcat....

 

[BDCarrillo]

Use an old radiator cap and drill a hole for a small hose barb. Screw the barb in and pump away with your brake bleeder pump (We all have one, right?)