2021 F150 Powerboost "Coolant overheating" error

[VAS]

I have a new 2021 Powerboost with 3K miles. Just completed my first RV tow, spread out over two days. Once each day I got a warning that the coolant was overheated. First day, ran for a hundred miles and stopped for a break/lunch. Turned on the AC. Ran for another hundred or so (almost 2 hours) and got the 1st warning. Pulled over right away and let it cool for 30 minutes. Did a visual on the coolant resevoir. Was not low. Completed day 1 without the AC on and no more warnings. Next morning, checked the coolant again, not low, so headed out. Pretty much the same scenario. Only this time, it took less than a hour of the AC being on when the warning came on. Sat for 30 minutes again. And again completed the rest of the trip without AC.

My questions are this:
1) How is the temperature gauge on my dashboard supposed to operate? Because, the whole time it was sitting right in the middle, at "50%". It never moved. When the warning message came on, the little temperature symbol turned red, that's it. Isn't the guage supposed to move as the temperature changes. Shouldn't I be able to tell its getting hot before the warning message appears? One of the pics on this thread shows the guage in about a "3/4" position when hot. I would have expected mine to work this way.
2) I've seen the pics others have posted where thier truck displays an actual temperature also. Mine did not do that either. Should it have??
3) Was my truck even overheated at all?? The guage didn't move. Could the warning message be in error??

Any other ideas?

8000 lb RV, highway driving at 60 MPH, mid 80s on day one, and cooler (about 80) on day two. My exact configuration is rated for 12,4000 lbs. Yes, I know there is a lot of "marketing" in that number. Hence, my RV at only 66% of that weight. I shouldn't be having this issue. I've read the the PB has the most robust coolant setup out there. Is that not true? The tow experience was fantastic... up until I got the first warning.

If I can't tow (well below the advertised weight limits) during summer months with the AC on, then it completely defeats the entire reason I upgraded to this truck!

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[Sbdavis1]

I’ve never experienced this with my 2021 PowerBoost but I can recommend using Forscan to change the gauges to the digital temp readout. This may give you more insight/warning.

 

[Oxford_Powerboost]

Was the message coolant overtemp, or “power reduced to lower engine temperature?”

if the latter, is your check engine light on for anything?

I ask because from my experience, the truck lies to you. I have used Forscan to turn on my digital temps and from research and talking to others - my “engine power reduced to lower engine temperature” message was actually NOT related to coolant temperature, at least at the point the coolant gauge reads it. Your gauge definitely should be rising if it’s truly overheating the coolant, and it’s been a common feature for a while that the digital temps pop up once it hits I believe 235, and it won’t reduce any power until 245.

In my case, the issue was due to the exhaust heat exchanger valve being stuck, not actual engine overtemp.

You’ll note in my pic a coolant temp of 205, which is a temp the 3.5 ecoboost runs at all day long. But I still had reduced power

 

[Snakebitten]

I second the suggestion to enable digital temps on the gauge cluster, but as Oxford_Powerboost pointed out, the digital temps are supposed to pop-on once the coolant temps reach a threshold and you still should have time to react to avoid limp mode.

I don't think he's experienced the notorious exhaust heat exchanger leak though because he would notice the loss of coolant in the main expansion tank.

Regardless, he is towing and I'd be curious what gear he is in at 60mph?
If the truck is in overdrive (8,9,10) the first thing I would try is to lock those gears out and run no taller gear than 7th.

Far less heat being dumped into the coolant loop from the turbos, and more rpms to get that water pump to do its job too. Win/Win when it comes to Engine Coolant Temps.

 

[Oxford_Powerboost]

I second the suggestion to enable digital temps on the gauge cluster, but as Oxford_Powerboost pointed out, the digital temps are supposed to pop-on once the coolant temps reach a threshold and you still should have time to react to avoid limp mode.

I don't think he's experienced the notorious exhaust heat exchanger leak though because he would notice the loss of coolant in the main expansion tank.

Regardless, he is towing and I'd be curious what gear he is in at 60mph?
If the truck is in overdrive (8,9,10) the first thing I would try is to lock those gears out and run no taller gear than 7th.

Far less heat being dumped into the coolant loop from the turbos, and more rpms to get that water pump to do its job too. Win/Win when it comes to Engine Coolant Temps.

Good point about gearing - and one reason I get a little on edge when people say they’re towing in normal and eco modes.
Slight correction though - I also never had the coolant leak from the heat exchanger. My issue with it was purely electronic. Coolant was full for the above pic

 

[Snakebitten]

Good point about gearing - and one reason I get a little on edge when people say they’re towing in normal and eco modes.
Slight correction though - I also never had the coolant leak from the heat exchanger. My issue with it was purely electronic. Coolant was full for the above pic

Agreed on towing in Normal or Eco.
I'm sure it's not a big deal for a utility trailer or something a couple of thousand pounds without a parachute of frontal area. But that shift strategy is begging for long steady turbocharger events, and as big a fan of the 3.5 Ecoboost as I have been for more than a decade, it's Achilles heal in summer heat towing is shedding heat. The guys that are well seasoned at doing so know how to work around it. They lock those gears out and substitute rpms for boost. If the temps still threaten the 240's, they get out of the gas enough to bring it back down.

The good news is it does recover really fast. Literally starts dropping in seconds.

I forgot about your exhaust heat exchanger actually being a faulty valve, was it?

 

[air2mag]

Glad for you posting this. It makes feel better about ordering my 5 liter

 

[Snakebitten]

I wish no truck malady on anyone, regardless of make or model. But purchasing any of them doesn't exempt you from potential issues.

 

[air2mag]

I agree with that. It still amazes me the longevity of these trucks. Sure you can get a bad one, but for the most part, with good maintenance, they last a long time. My 09 has 241k.

 

[Bird of prey]

Where were you driving, road conditions, flat road or mountains?

 

[VAS]

To all who replied... thank you so much for your comments and suggestions!!! I traded in my 2.7 Ecoboost for this 3.5 PowerBoost in order to do some RV towing. I am a nubie at it, but learning very fast.

Sbdavis1: Thanks for the forscan suggestion. I had read about Forscan a few months back, and now have a reason to give it a try.

Oxford: thanks for the photo. Love the visual aid and want my display like this. FYI: I never got a "power reduction" messages at all (thank goodness). At this point, my gut tells me the truck is lying to me, and is not overheating.... which assumes the guage itself is working properly (which never moved from the mid point).

Snakebit, I had just read Friday night about locking out the gears on another thread and will educate myself on how to do this as well. Seems its the right thing to do for RV towing needs. The other thread said it actually improved gas mileage while towing as well.... not sure about that, but we'll see.

Bird of prey: Day one was pretty flat driving on the Ohio Turnpike. Day two in PA was also fairly flat up to when I got the warning. After I turned off the AC, we did have a few hills to climb and decend, but did not get any warnings after the initial one. Again, the AC was off by this time.

My to-do list from your suggestions....
1) Forscan so I can get digital temp all the time and have better insight into my truck performance, characteristics, and overall status.
2) Lock out gears 8,9,10 to reduce heat from the turbo when I tow.

My next tow is targeted for mid August. I will post an update on how it goes (around the 21st).

Thanks so much!!!!

 

[Atlee]

To all who replied... thank you so much for your comments and suggestions!!! I traded in my 2.7 Ecoboost for this 3.5 PowerBoost in order to do some RV towing. I am a nubie at it, but learning very fast.

Sbdavis1: Thanks for the forscan suggestion. I had read about Forscan a few months back, and now have a reason to give it a try.

Oxford: thanks for the photo. Love the visual aid and want my display like this. FYI: I never got a "power reduction" messages at all (thank goodness). At this point, my gut tells me the truck is lying to me, and is not overheating.... which assumes the guage itself is working properly (which never moved from the mid point).

Snakebit, I had just read Friday night about locking out the gears on another thread and will educate myself on how to do this as well. Seems its the right thing to do for RV towing needs. The other thread said it actually improved gas mileage while towing as well.... not sure about that, but we'll see.

Bird of prey: Day one was pretty flat driving on the Ohio Turnpike. Day two in PA was also fairly flat up to when I got the warning. After I turned off the AC, we did have a few hills to climb and decend, but did not get any warnings after the initial one. Again, the AC was off by this time.

My to-do list from your suggestions....
1) Forscan so I can get digital temp all the time and have better insight into my truck performance, characteristics, and overall status.
2) Lock out gears 8,9,10 to reduce heat from the turbo when I tow.

My next tow is targeted for mid August. I will post an update on how it goes (around the 21st).

Thanks so much!!!!

I have found if I am running in 7th gear while towing, the RPM's are up, I can stay out of turbo boost longer, and if I'm not in boost mood I should be using a little less gasoline.

 

[Kanuck]

I second the suggestion to enable digital temps on the gauge cluster, but as Oxford_Powerboost pointed out, the digital temps are supposed to pop-on once the coolant temps reach a threshold and you still should have time to react to avoid limp mode.

I don't think he's experienced the notorious exhaust heat exchanger leak though because he would notice the loss of coolant in the main expansion tank.

Regardless, he is towing and I'd be curious what gear he is in at 60mph?
If the truck is in overdrive (8,9,10) the first thing I would try is to lock those gears out and run no taller gear than 7th.

Far less heat being dumped into the coolant loop from the turbos, and more rpms to get that water pump to do its job too. Win/Win when it comes to Engine Coolant Temps.

A little off topic... Has anyone know if temps be enabled on a 21 XLT with 302A package?

 

[Snakebitten]

I don't think the Forscan gurus have cracked the Gen14 8" IPC yet. Which is a bummer since it's so similar to the previous generations higher trim cluster which has the Forscan hack.

 

[thudnblunder]

Far less heat being dumped into the coolant loop from the turbos, and more rpms to get that water pump to do its job too. Win/Win when it comes to Engine Coolant Temps.

Good point on heat from the turbos but isn’t the coolant pump electrical?

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