[Sirikenewtron]

Put a T-stat on order today. Linky below. I’ll pick up some fresh fluid locally. I have been running between 215 and 220 unloaded at interstate speeds.

More Information for MOTORCRAFT RT1252

After swapping it out with that thermostat you should see about 201° give or take on the interstate unloaded not towing. That's been my experience anyways, it did exactly what I was hoping for.

 

[John Zwemer]

I had a similar experience with my 2016 F150 3.5 EcoBoost. I changed the thermostat with suggested
HL3Z - 8575 - B Thermostat (Rev B), HL3Z - 8255 - A O-Ring. When towing my trail trailer (2021 Keystone Cougar, GVRW 10,500) I was till overheating when the engine would rev to climb hills. It would drop to normal range when on flat ground.

I took it into the shop this week and they have suggested a radiator change since I already did the thermostat.

Has anyone else had this issue? Is there anything else I should be looking at or for that would cause the overheating prior to making the radiator swap.

 

[FanaticalKilla]

I had a similar experience with my 2016 F150 3.5 EcoBoost. I changed the thermostat with suggested
HL3Z - 8575 - B Thermostat (Rev B), HL3Z - 8255 - A O-Ring. When towing my trail trailer (2021 Keystone Cougar, GVRW 10,500) I was till overheating when the engine would rev to climb hills. It would drop to normal range when on flat ground.

I took it into the shop this week and they have suggested a radiator change since I already did the thermostat.

Has anyone else had this issue? Is there anything else I should be looking at or for that would cause the overheating prior to making the radiator swap.

Welcome to the forum John!
-When towing are you towing in OD aka 5th or 6th. If you tow in 4th and get the rev's up, they tend to cool better.
-Water pump should be inspected as well.
-If you are going to change the radiator. I would also recommend going to a upgraded unit with increased cooling capacity/thicker cores like say a Full Race unit.
-Grill shutters need to be confirmed they are full open.
-Also what are your trans temps?

 

[John Zwemer]

Towing in 5th locked out 6th, down shifts to 4th going uphill.

Temps steady around 235-240 saw a spike to 245.

I did order an upgraded radiator. I’ll check the shutters and water pump.

 

[FanaticalKilla]

Towing in 5th locked out 6th, down shifts to 4th going uphill.

Temps steady around 235-240 saw a spike to 245.

I did order an upgraded radiator. I’ll check the shutters and water pump.

I would consider running in 4th and maybe try running a little slower. Try and keep the engine out of constant boost.

 

[2016XLT4x4]

I don't just lock out my overdrives. I watch my boost gauge and lock out gears accordingly.

 

[nick.simonye]

I've replaced thermistat with a lower temp one, I've replaced water pump, I've vacuumed serviced the coolant, I've disconnect the shutters. Nothing has helped mine.. if I'm towing temp goes up while going down hill.. not towing the temp goes up also. Just slowing down after doing freeway speeds.. 150,000 miles on mine.. 2019.

 

[FanaticalKilla]

I've replaced thermistat with a lower temp one, I've replaced water pump, I've vacuumed serviced the coolant, I've disconnect the shutters. Nothing has helped mine.. if I'm towing temp goes up while going down hill.. not towing the temp goes up also. Just slowing down after doing freeway speeds.. 150,000 miles on mine.. 2019.

How hot are we talking? Is that your only complaint?

How long does the temp go up heading down a hill. Mine will do that too for maybe a couple seconds. I personally think it's normal. Mine will gain 5 degrees or so then start dropping hard.

 

[Justinjs]

I've replaced thermistat with a lower temp one, I've replaced water pump, I've vacuumed serviced the coolant, I've disconnect the shutters. Nothing has helped mine.. if I'm towing temp goes up while going down hill.. not towing the temp goes up also. Just slowing down after doing freeway speeds.. 150,000 miles on mine.. 2019.

A couple questions, how much are you towing, how fast are you driving, is the thermostat a motorcraft one (solved my high temp as well as several others), what temp are you seeing?

 

[nick.simonye]

How hot are we talking? Is that your only complaint?

How long does the temp go up heading down a hill. Mine will do that too for maybe a couple seconds. I personally think it's normal. Mine will gain 5 degrees or so then start dropping hard.

It varies. I've had it go hi enough that the truck lowers power to help cool down. I've been debating on getting an auxiliary inline pump. I think it's just a bad design. My radiator is clean and clear so I doubt that it's the issue unless it's just to small. If temp wouldn't go up, truck would be great. Plenty of power and handles nicely.

 

[FanaticalKilla]

It varies. I've had it go hi enough that the truck lowers power to help cool down. I've been debating on getting an auxiliary inline pump. I think it's just a bad design. My radiator is clean and clear so I doubt that it's the issue unless it's just to small. If temp wouldn't go up, truck would be great. Plenty of power and handles nicely.

Cooling system are pretty small on the base cooling package trucks IMO. I would look at going to a Full Race radiator. Lots more cooling and capacity.

 

[FanaticalKilla]

A couple questions, how much are you towing, how fast are you driving, is the thermostat a motorcraft one (solved my high temp as well as several others), what temp are you seeing?

Motorcraft is the only way to go.

 

[Gord0]

It varies. I've had it go hi enough that the truck lowers power to help cool down. I've been debating on getting an auxiliary inline pump. I think it's just a bad design. My radiator is clean and clear so I doubt that it's the issue unless it's just to small. If temp wouldn't go up, truck would be great. Plenty of power and handles nicely.

Make sure all the lines running to and from your degass tank are clear.

 

[rogerg1985]

Sure hope this helps. I have the exact same problem after changing my water pump and thermostat. I'll let you know next week. Just ordered those part numbers. Thanks

 

[Justinjs]

Sure hope this helps. I have the exact same problem after changing my water pump and thermostat. I'll let you know next week. Just ordered those part numbers. Thanks

Did you get a motorcraft t stat?

 

[rogerg1985]

Did you get a motorcraft t stat?

I just ordered the OEM part off of ford with that part number he supplied. The one that does not seem to be working as well is from oreilly's, but I can check to see if it is motorcraft.

 

[Justinjs]

I just ordered the OEM part off of ford with that part number he supplied. The one that does not seem to be working as well is from oreilly's, but I can check to see if it is motorcraft.

I had horrible luck with an aftermarket replacement, motorcraft seems to do the trick.

 

[rogerg1985]

I had horrible luck with an aftermarket replacement, motorcraft seems to do the trick.

Yeah, just double checked. It's definitely motorcraft. I didn't realize the aftermarket one would be this way. It's not overheating but it's running hot. 65mph and I'm running like 230-235. Very frustrating. I am really not looking forward to pulling everything off again, but at least it will go quicker this time.

 

[Justinjs]

Yeah, just double checked. It's definitely motorcraft. I didn't realize the aftermarket one would be this way. It's not overheating but it's running hot. 65mph and I'm running like 230-235. Very frustrating. I am really not looking forward to pulling everything off again, but at least it will go quicker this time.

Same thing happened to me, let us know how it goes.

 

[rogerg1985]

Same thing happened to me, let us know how it goes.

Much thanks to the OP. Changed the thermostat to a motorcraft OEM and seems to fixed the running hot problem. Even pulled a trailer without issues.