Erratic Cooling

[Swacer]

Man that sucks! Im pointing to the thermostat, though I wonder why it shit the bed so soon. There aren't many other parts associated to the cooling system other than the water pump. Does anyone know wether the impeller is plastic and could be worn? Maybe tolerances are worn and its not moving the same amount of coolant?

I agree, that would be a thermostat at 30k miles and now at nearly 60k miles.

 

[Swacer]

I don't think there's a problem, mine behaves the same way for 9 1/2 years in the winter months.
1 1/2 years NA and 8 years Supercharged.
I run a 170 thermostat. It does what yours does just cooler.

Man that sucks! Im pointing to the thermostat, though I wonder why it shit the bed so soon. There aren't many other parts associated to the cooling system other than the water pump. Does anyone know wether the impeller is plastic and could be worn? Maybe tolerances are worn and its not moving the same amount of coolant?

I had the chance this weekend to replace the thermostat. I saw people on other F150 forums say that changing a thermostat was like a 35 minute job. I wanna know how rapidly they are moving, because on my first try to replace this, it took me dang near 3 hours with the first air purge.

I found the way to do it where you only pull the top hose off the radiator and tie that back, and then go after the thermostat. The moment i popped the thermostat out, there was a HUGE burp in the system, then probably 1/2 gallon went onto my floor. I strongly believe that the dealership when they did my coolant or heater core (both were done 5k miles apart) didn't bleed the system correctly and I had a huge air bubble. So I'm not sure if the issue was the thermostat or the huge air bubble. It would also explain why I have brief periods when my heat was running, where it would get cool. If it was the thermostat, thats crap if one is dying every 30k miles.

I put the new thermostat in, filled up with coolant, let the air bleed to the reservoir (eaten about 1/2" of coolant) and my entire drive today, the temp on the dash didn't move at all away from normal temp. It was quite refreshing.

MTF, I have a lower temp thermostat in my cammed camaro, and it doesn't overcool like that, even on the few days its like 35 degrees.

Thanks for the help and input everyone

 

[MTF]

I did reread your post and I see now you didn't say anything about a cooler thermostat.
So apparently you had a faulty thermostat.
Glad you got it figured out.​

Mine is not over cooling, 170 thermostat does just what it's suppose to do.
If I don't put a load on the engine it will cool down to 170

I've changed my thermostat at least a dozen and half times, never had to do any kind of procedure to burp the system.
When I'm done swapping out the thermostat,
I leave the radiator cap off until the engine gets up to operating temp and you can tell when that happens if you look down the radiator fill opening, water will flow quite fast and drop down in level.
Just before that happens it will rise a bit, because the antifreeze is starting to expand and entering the radiator through the bottom hose.
I then proceed to fill what ever the system needs, which is close to the amount I siphoned out.
I'll put the cap on and throw the little bit left into the over-flow tank.

I also make sure the over flow tube is not hanging down too low or kinked in anyway.
I actually cut the tube shorter so at no point is the tube lower than the radiator cap.
I've run into that problem on other vehicles, with a big loop in the tube the air has a hard time getting to the over-flow tank.

I should also mention I did buy a new radiator cap two years ago, it started leaking.
I'm pointing that out because if the cap is bad also it will suck in air from the cap and not the antifreeze from over-flow tank, just something to think about.

The Raptors radiator cap is 20 psi.

https://www.tascaparts.com/oem-parts/ford-radiator-cap-6l2z8100ac/?c=Zz1jb29saW5nLXN5c3RlbSZzPXJhZGlhdG9yLWFuZC1jb21wb25lbnRzJmk9TUEwOTA4MTUmcj00JmE9Zm9yZCZvPWYtMTUwJnk9MjAxMCZ0PXN2dC1yYXB0b3ImZT02LTJsLXY4LWdhcw==

 

[onthebrake]

I had the chance this weekend to replace the thermostat. I saw people on other F150 forums say that changing a thermostat was like a 35 minute job. I wanna know how rapidly they are moving, because on my first try to replace this, it took me dang near 3 hours with the first air purge.

I found the way to do it where you only pull the top hose off the radiator and tie that back, and then go after the thermostat. The moment i popped the thermostat out, there was a HUGE burp in the system, then probably 1/2 gallon went onto my floor. I strongly believe that the dealership when they did my coolant or heater core (both were done 5k miles apart) didn't bleed the system correctly and I had a huge air bubble. So I'm not sure if the issue was the thermostat or the huge air bubble. It would also explain why I have brief periods when my heat was running, where it would get cool. If it was the thermostat, thats crap if one is dying every 30k miles.

I put the new thermostat in, filled up with coolant, let the air bleed to the reservoir (eaten about 1/2" of coolant) and my entire drive today, the temp on the dash didn't move at all away from normal temp. It was quite refreshing.

MTF, I have a lower temp thermostat in my cammed camaro, and it doesn't overcool like that, even on the few days its like 35 degrees.

Thanks for the help and input everyone

Ya, it took me 2-3 hours to replace my thermostat too ! We don't do it for a living so are methodical about the process. That's all good man. My truck runs so much cooler and my fans aren't on 24/7 anymore after changing my thermostat. Mine 2017 thermostat was absolutely faulty. That's real.