2018 F150 Overheating

[HottyToddy]

Looking for some help as my local ford dealer was very "meh" about offering up anything.

2018 F150 Lariat
75k miles
3.5 ecoboost, FX4, tow package

Truck overheats ~slightly~ after 45 mins or so of driving on the interstate. My temperature gauge is digital and usually shows an arbitrary level of just below half. After 45 mins or so on the interstate, I'll hit a hill and the truck drop shifts to maintain ~74mph with cruise control. When this happens, depending on the size of hill, a number will appear above my gauge. Starts at 228*, and increases if I continue to let it cruise control up the hill. If I kill the cruise control and let it coast it quickly drops down to 226* and below and the number goes away. I've never let it go above 232*. According to ford, 230+ is mildly overheating with damage not occurring until 245+. If I stay below 65mph it doesn't have issues even when it drop shifts up the hills.

Coolant is topped off and rides at the max fill line. Radiator is clear (with the exception of a fly or two, but no major blockages). My guess is either the high fan isn't working (or its sensor isn't working), or the thermostat has gone bad. Any other ideas or ways to test these two theories?

Thanks in advance!

 

[JCDEERMAN]

No clue, but I think those are some good guesses. I have a 2015 with same engine. Mine doesn't overheat, but every once in a while it will smoke under the hood and I'm unable to figure out where it's coming from.

If you have any recalls on it, I'd take it in to fix those and get them to check that out. I hate going to the dealerships too, but they'll cover the recalls. I had 4 of them and had one minor thing done. Got out of there less than $200. Couldn't believe it.

Best of luck!

 

[Jcalder]

If it's easy to get to, a thermostat should be an inexpensive part to replace

 

[backyardtndeer]

Have you ever changed the coolant? Some manufacturers suggest draining and changing the coolant every 5 years. Some suggest flushing. I usually use prestone flush when I do a cooling system.

 

[FLTENNHUNTER1]

Radiator shutter assembly issue? Does the 3.5 EB have one?

 

[gtk]

Been through this. Replace the thermostat. There is an updated thermostat for these vehicles. Mine had a small tab broken off and wouldn't allow the thermostat to open all the way.

I have a 2018 F150 4x4 with 3.5 eco-beast , FX4 and towing package. My truck spent months in the shop trying to resolve the issue. Finally i googled the solution and provided to the tech, who reluctantly tried and was amazed it worked They had replaced my radiator plus a bunch of other stuff (under warranty).

My issues started in Montana while pulling my camper. All of a sudden when going up hills and the turbos were working harder, my temp gauge would start to creep up. Going down hill, the temp would go down. I just learned to downshift and stay out of the turbos when possible, to get around this issue (most of the time). Then one time in the heat of the summer, my engine started heating up and the transmission started blowing fluid out of the vent. This happened a couple of times over several months. Turns out the tolerances for these engines are so tight, just a few degrees of engine temp increase was causing my transmission fluid to "heat up" instead of "cool off" when going thru the radiator & intercooler.

 

[HottyToddy]

Have you ever changed the coolant? Some manufacturers suggest draining and changing the coolant every 5 years. Some suggest flushing. I usually use prestone flush when I do a cooling system.

Haven't changed it. When it first happened I checked coolant and it was definitely low (none in the reservoir when cold). Topped it off with new coolant and figured I would be good, but alas it still happens regularly when driving an hour +

 

[HottyToddy]

Radiator shutter assembly issue? Does the 3.5 EB have one?

Not sure. Unfamiliar with what this is

 

[HottyToddy]

Been through this. Replace the thermostat. There is an updated thermostat for these vehicles. Mine had a small tab broken off and wouldn't allow the thermostat to open all the way.

I have a 2018 F150 4x4 with 3.5 eco-beast , FX4 and towing package. My truck spent months in the shop trying to resolve the issue. Finally i googled the solution and provided to the tech, who reluctantly tried and was amazed it worked They had replaced my radiator plus a bunch of other stuff (under warranty).

My issues started in Montana while pulling my camper. All of a sudden when going up hills and the turbos were working harder, my temp gauge would start to creep up. Going down hill, the temp would go down. I just learned to downshift and stay out of the turbos when possible, to get around this issue (most of the time). Then one time in the heat of the summer, my engine started heating up and the transmission started blowing fluid out of the vent. This happened a couple of times over several months. Turns out the tolerances for these engines are so tight, just a few degrees of engine temp increase was causing my transmission fluid to "heat up" instead of "cool off" when going thru the radiator & intercooler.

This is what I've been thinking. Can't imagine it's more than a couple hundred to get a thermostat swapped (if I can't do it myself). Was tempted to just try it and hope it works vs paying them hundreds in diagnostics just to "not find" anything wrong.

 

[Wade195]

Make sure coolant level is correct.

Also confirm antifreeze concentration is correct. To high a concentration and the heat will not dissipate correctly.

Confirm it's truly get hot.

Check the temperature difference from the top to bottom tank. Typical temperature drop should be approximately 10 to 12 degrees.


If you are seeing more drop than that you more than likely have a flow issue.

Also make sure the radiator fins are clear the whole area of the radiator. If it has a condenser in front of radiator confirm it's clear.

Feel bottom radiator hose and confirm it's not collapsing.

Last check for compression in cooling system.

 

[BMan]

Been through this. Replace the thermostat. There is an updated thermostat for these vehicles. Mine had a small tab broken off and wouldn't allow the thermostat to open all the way.

I have a 2018 F150 4x4 with 3.5 eco-beast , FX4 and towing package. My truck spent months in the shop trying to resolve the issue. Finally i googled the solution and provided to the tech, who reluctantly tried and was amazed it worked They had replaced my radiator plus a bunch of other stuff (under warranty).

My issues started in Montana while pulling my camper. All of a sudden when going up hills and the turbos were working harder, my temp gauge would start to creep up. Going down hill, the temp would go down. I just learned to downshift and stay out of the turbos when possible, to get around this issue (most of the time). Then one time in the heat of the summer, my engine started heating up and the transmission started blowing fluid out of the vent. This happened a couple of times over several months. Turns out the tolerances for these engines are so tight, just a few degrees of engine temp increase was causing my transmission fluid to "heat up" instead of "cool off" when going thru the radiator & intercooler.

gtk, what size/weight camper were you pulling at the time?

 

[gtk]

gtk, what size/weight camper were you pulling at the time?

Small 26'er. I think dry weight is like 4700 lbs. It pulls it great, but when in the mountains it likes to get into the turbos

 

[gtk]

This is what I've been thinking. Can't imagine it's more than a couple hundred to get a thermostat swapped (if I can't do it myself). Was tempted to just try it and hope it works vs paying them hundreds in diagnostics just to "not find" anything wrong.

Make sure you get the newer "replacement" thermostat . Not even sure if they sell the older one, but that would be my luck if doing it myself.. I'd put the same problem back in it

 

[backyardtndeer]

This is what I've been thinking. Can't imagine it's more than a couple hundred to get a thermostat swapped (if I can't do it myself). Was tempted to just try it and hope it works vs paying them hundreds in diagnostics just to "not find" anything wrong.

Looks like pretty simple and straight forward procedure . If it were mine, after changing the thermostat, I would run a cycle of prestone flush through it before adding in the new antifreeze.

 

[HottyToddy]

Make sure you get the newer "replacement" thermostat . Not even sure if they sell the older one, but that would be my luck if doing it myself.. I'd put the same problem back in it

Do you know if you (or the dealer) replaced just the thermostat or the whole assembly? Looks like ~$20 vs ~$105

 

[HottyToddy]

Okay - another question about the coolant reservoir. My truck only has a max and min. Not a hot and cold. Are the max and min the levels when hot or when cold?

 

[HottyToddy]

Looks like pretty simple and straight forward procedure . If it were mine, after changing the thermostat, I would run a cycle of prestone flush through it before adding in the new antifreeze.

Does look really straightforward. Dealer said $300 for thermostat, $400 for assembly (out the door. Labor and taxes included).

 

[mike52]

Easy fix. Change the radiator cap.

 

[gtk]

Do you know if you (or the dealer) replaced just the thermostat or the whole assembly? Looks like ~$20 vs ~$105

I do not. I believe just the thermostat, but would have to find my paperwork to be certain.

 

[HottyToddy]

Easy fix. Change the radiator cap.

If I'm not losing fluid, why would the radiator cap be an issue?