Hi, wondering if any one knows what happened the other day.Here's the story. I just changed my coolant . I put 3gals. coolant and 3gals. distilled water with 1.5 bottles of penncool.. drove around for a couple days every thing ran fine exept temp gauge seemed to be running a little cooler than normal.. Then went up a 12 mile long steep mountain pass . I was keeping a close eye on the temp and the temp was fine for the 1st 4 or 5 miles then it suddenly pegged as hot as it gets. I pulled over and opened the hood coolant was boiling out the resavoir and the top radiator hose was collapsed. I squeezed the hose as open as I could but it still didn't open much. So I drove the truck down hill and it was still pegged for a minute or so then the temp went back to a little below normal very fast . The I went to a NAPA store that was close by I replaced the coolant which was only what was in the resivoir and only about a half a gallon into the radiator. Then I attempted the pass again and went all the way up, again a little below normal temp. And the top radiator hose was fine.Is this the thermastat going bad? The top hose collapsing must be a sighn of something.Anyway has any of you seen or heard of this before? Any insight will be appreciated thanks Norm

 

hey there... sounds like it might just be air in the system, just did a coolant change and the top hose will suck closed under load if you the systems not full. If the Thermostat's gone (stuck shut) then the top hose would be rock hard and wide open. (just changed that, hence the coolant change).
Possible of course it (stat) could be stuck open, which logically could keep air at the top... someone with more knowledge will be along in a bit and give you something concrete.
Good Luck - R

 

First check the lower hose has a shape retaining coil spring in it..... the spring stops the lower hose from sucking closed when high RPMs are being used.

I would like to advise check the Tstat and install the right one. While there check the small check ball is free and rattles in the upper coolant manifold.

Some times the coolant does not fill the heads completely if air is not bled off by the check ball. You can substitute the removal of the upper heater hose on the water pump to assist in air removal when filling.

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https://www.ford-trucks.com/forums/s...89#post2197889