I,just had the radiator repaired on the truck and I replaced the thermostat as well due to a leaking housing and the wrong thermostat in there.
Now I just can't get the temp on the truck to go over 180*.
I put an OEM Motorcraft stat in there and replaced some aftermarket stat.I,filled the system up with about 4 and 1/2 gallons of coolant but the temp will not go over 180*.i have a thermometer in th cap hole to check the coolant temp.I just want the thing to open so I can continue to refill the system.I know air bubbles in that system can be a problem to get out sometimes.
I don't want to just put the cap back on cause of fear of trapping air and causing a mess.I THIS THING EVER GONNA OPEN?
Any suggestions?

 

Fill it and drive it. There is a little bleeder in the tstat housing that is likely plugged. When i did my t stat i dumped in what i could and went for a drive. She got up to 230-240 before it finally opened the first time. No problems since.

If you dont like that route, you could loosen the t-stat housing while its running.. if you can. If everything is installed right, it should warm right up same as normal. Make sure to have the heater bypass closed so it will circulate the heater core.

 

If you are in the freeze zone, stick a piece of cardboard in front of the radiator to assist in it's warm up ...

Or work it!

-Enjoy
fh : )_~

 

Tried doing that on mine. Waited 20-something minutes on a warm SoCal day for the t-stat to open up after draining both the radiator and the block. Finally got fed up and decided to go around the block. I got to the end of my street before the temp gauge pegged out, the ENGINE TEMP light came on, and I about crapped myself. I got it back to the house, shut it down, and the radiator that HAD been full just a couple minutes ago was now nearly bone dry.

My recommendation: have patience. Maybe hold the throttle open for a bit, but otherwise just hang out and be Johnny-on-the-spot to top it off because once that t-stat opens, it goes QUICK.

Mike

 

Did that and had the A/C going as well.It only got up to 180* but the truck is in the shade and it was about 60* today.Im gonna park it the sun tomorrow and give it another whirl.
I will report back !!!

 

It might help to point the truck uphill to get the rad cap up higher.

 

fill the Overflow Tank..and drive it...if the upper hose gets warm its opening..the motercraft T stat..has small opening...to let out steam..and air..will open a small amount only...if no load on engine..

 

The hose is getting warm. I will give that a shot in the am.its been a bit chilly down here and we had snow last night.its gonna warm up this week.
Thanks

 

Take a hose off the heater core when you are filling the coolant. It will let the air out of the block. when coolant comes out hook it back up and contiune filling. If that doesn't work I would get a new t-stat.

 

I think one of the key things thats been mentioned, these trucks dont' produce much heat just idling. You need to get the revs up putting a load on the engine. Otherwise you're just sitting there burning fuel.

Disconnecting a heater hose and filling it through the hose is a great idea! That will allow you to get a lot more of the air out of the system pretty easily. And if the overflow tank is filled up, when the air inside gets warm and expands it will push out, and then suck coolant back in when it cools.