2020 Expy Overheating at Highway speeds.

[Jozef Zoldos]

So. I have a 2020 Expedition Platinum Max with 60K miles. No trailer tow package. Over the past 2 weeks, I noted some mild overheating when driving highway speeds. The temperature would appear above the Cold/Hot water temp guage as shown below.

Never noticed this before. Hooked up a BlueDriver code reader into the OBD port and looked at live data while running at highway speeds. Generally speaking, when driving at 85MPH (I know this is faster than I should drive) temp would creep up and the numbers would be visible when the temp hits 228 degrees F. When I took my foot off the gas, the temp crept up 4-5 degrees before it would come down. Highest I saw it go was 239F. Did not see these highter temps when driving less than 80 MPH but would stay somewhere between 115 and 125F. There were no codes thrown. No warnign lights. And the car seemed to drive normally during the entire time. (also no police sirens). The ambient temp was about 35F. I was not towing anything and I was not loaded down (except for my wife and she is not that heavy...lol).

I looked thru the forum and saw this topic posted several times with several potential problems. I think all were in agreement that this is not normal. I am not a mechanic but I have been doing quite a bit of wrenching as if late. Intuitively, I could think of several potential issues that could cause this problem as follows:
- bad thermostat
- bad water pump
- bad CHT (cylinder head temp) sensor
- bad radiator
- low radiator fluid
- bad Active Grille Shutter System

I talked withseveral individuals about this and, because there was no code or alarm being tripped, the diagnosis would be a little tough. I figured bad radiator was unlikely. Fluid levels were all good and there were not obvious radiator leaks. The Active Grille Shutter seemed to work well on start-up (supposed to cycle open and closed) and I also read that if it were not working, an error code would be sent by the PCM. Therefore, by process of elimination, What I had left was bad thermostat, water pump, or CHT sensor. I read that Ford re-designed it's thermostats in 2022 and, indeed, the OEM thermostat that I picked up at the dealership was a little different (original part number was HL3Z-8575-AA and new part number was HL3Z-8575-B). The link to the new part number is.... https://ford.oempartsonline.com/oem...lvbiZ5PTIwMjAmdD1wbGF0aW51bSZlPTMtNWwtdjYtZ2F. I figured the easiest and most likely attempt to treat the problem successfully was to try a new thermostat. so that is what I tried first. Fix was pretty easy. Took about half an hour. I needed to top up the coolant fluid when I was done.

Result: Took it for a 1 hour test spin with some hard driving and could not get the temp above 215F. So for now, problem appears fixed. and fix was pretty easy and cheap.

Just posting this because this seems to be a frequent issue on this forum with no clear cut solution or thought process as to how to approach it. As mentioned previously, I am not a mechanic and I am sure that there are much smarter people on this forum that can chime in straighten me out if I did not approach this properly. Please feel free to add to this post so that future lurkers can use it as a reference.

Thanks

Joe Z
2020 Ford expedition Platinum Max.

 

[Going_Going_Gone]

I just had the thermostat in our 2019 replaced as a preventative measure.

 

[wakeboarder]

To eliminate the cylinder head temperature sensor as a possibility, look at the transmission temperature while hot. If it is within 10°F of the engine temperature, the the cylinder head temperature sensor is fine.

 

[Jozef Zoldos]

To eliminate the cylinder head temperature sensor as a possibility, look at the transmission temperature while hot. If it is within 10°F of the engine temperature, the the cylinder head temperature sensor is fine.

Great point. This helps with diagnosis.

 

[RABAYL01]

So. I have a 2020 Expedition Platinum Max with 60K miles. No trailer tow package. Over the past 2 weeks, I noted some mild overheating when driving highway speeds. The temperature would appear above the Cold/Hot water temp guage as shown below.
View attachment 79674
Never noticed this before. Hooked up a BlueDriver code reader into the OBD port and looked at live data while running at highway speeds. Generally speaking, when driving at 85MPH (I know this is faster than I should drive) temp would creep up and the numbers would be visible when the temp hits 228 degrees F. When I took my foot off the gas, the temp crept up 4-5 degrees before it would come down. Highest I saw it go was 239F. Did not see these highter temps when driving less than 80 MPH but would stay somewhere between 115 and 125F. There were no codes thrown. No warnign lights. And the car seemed to drive normally during the entire time. (also no police sirens). The ambient temp was about 35F. I was not towing anything and I was not loaded down (except for my wife and she is not that heavy...lol).

I looked thru the forum and saw this topic posted several times with several potential problems. I think all were in agreement that this is not normal. I am not a mechanic but I have been doing quite a bit of wrenching as if late. Intuitively, I could think of several potential issues that could cause this problem as follows:
- bad thermostat
- bad water pump
- bad CHT (cylinder head temp) sensor
- bad radiator
- low radiator fluid
- bad Active Grille Shutter System

I talked withseveral individuals about this and, because there was no code or alarm being tripped, the diagnosis would be a little tough. I figured bad radiator was unlikely. Fluid levels were all good and there were not obvious radiator leaks. The Active Grille Shutter seemed to work well on start-up (supposed to cycle open and closed) and I also read that if it were not working, an error code would be sent by the PCM. Therefore, by process of elimination, What I had left was bad thermostat, water pump, or CHT sensor. I read that Ford re-designed it's thermostats in 2022 and, indeed, the OEM thermostat that I picked up at the dealership was a little different (original part number was HL3Z-8575-AA and new part number was HL3Z-8575-B). The link to the new part number is.... https://ford.oempartsonline.com/oem...lvbiZ5PTIwMjAmdD1wbGF0aW51bSZlPTMtNWwtdjYtZ2F. I figured the easiest and most likely attempt to treat the problem successfully was to try a new thermostat. so that is what I tried first. Fix was pretty easy. Took about half an hour. I needed to top up the coolant fluid when I was done.

Result: Took it for a 1 hour test spin with some hard driving and could not get the temp above 215F. So for now, problem appears fixed. and fix was pretty easy and cheap.

Just posting this because this seems to be a frequent issue on this forum with no clear cut solution or thought process as to how to approach it. As mentioned previously, I am not a mechanic and I am sure that there are much smarter people on this forum that can chime in straighten me out if I did not approach this properly. Please feel free to add to this post so that future lurkers can use it as a reference.

Thanks

Joe Z
2020 Ford expedition Platinum Max.

Thanks for posting Joe! What would the Transmission temp say? Your picture shows all normal as expected... also, so the temp number above the gauge only showed up when the temp went up? Been wanting to do this thermostat for the longest time to ease Transmission Temps.

 

[Jozef Zoldos]

Thanks for posting Joe! What would the Transmission temp say? Your picture shows all normal as expected... also, so the temp number above the gauge only showed up when the temp went up? Been wanting to do this thermostat for the longest time to ease Transmission Temps.

Sorry for the late response. Somehow, I do not get alerts whenever someone responds.

Regarding the temp showing up on the display, it shows up automoatically whenever the temp gets over 228F. When the temp drops below that number, the digital portion of the temp display goes away. I have read that there is a way to turn that number on full time with a simple Forecan modification to the PCM. I do not have Forscan and have not done that (yet).

Regarding the transmission temp, I am not 100 percent certain as I did not look at the transmission temps closely at the time when my engine was running hot. I did not know that the transmission temp correlated with the engine temp as posted by previous comment by Wakeboarder. I did, however, glance at the transmission temp when she was running hot before I changed the thermostat and, as I recall, the tranmission temp was running hotter than it is now. I think it was in the 220s. Now that the thermostat has been changed, I have been keeping my eye on the engine and tranmission temps. It is just like Wakeboarder claimed above, the transmission temp is about 10 degrees cooler than the engine temp and the engine temp runs between 200F and 208F at thighway speeds.

 

[acy540]

New to the EXP club but been reading about all the threads on heat. Not used to the temps these things run. I just picked up a 2018 with 100k on it. Cooling on the hwy looks to run from 215 to 226 and trans 200 to 207. As far as I know it does not have a HD cooling /tow package. I have been running F150's for the last 20 yrs. I had a 2018 diesel that ran much cooler and solid as a rock with forscan numbers under 200 degrees when towing.

My question is does any one have part numbers for the new thermostat, ( isee that in the post)
HD radiator hopefully one good for towing
Trans cooler " " " " "

I want to get into a more comfort zone ( mentally ) if possible.

Any help on the numbers would be great and tricks on installation. More on the trans cooler and if elimanating the stock version and going directly from hte trans to the cooler. Are there special hoses required?

Thanks to all

Acy540

 

[Jozef Zoldos]

The part number for the new thermostat was HL3Z-8575-B. A youtube video that I found in the internet is https://youtu.be/S0Kabry6I3M?si=3lGwi_vKNYOg-Qa6. You have to remove the air intake to get access. Whole thing takes about 15-30 minutes.

 

[Jozef Zoldos]

New to the EXP club but been reading about all the threads on heat. Not used to the temps these things run. I just picked up a 2018 with 100k on it. Cooling on the hwy looks to run from 215 to 226 and trans 200 to 207. As far as I know it does not have a HD cooling /tow package. I have been running F150's for the last 20 yrs. I had a 2018 diesel that ran much cooler and solid as a rock with forscan numbers under 200 degrees when towing.

My question is does any one have part numbers for the new thermostat, ( isee that in the post)
HD radiator hopefully one good for towing
Trans cooler " " " " "

I want to get into a more comfort zone ( mentally ) if possible.

Any help on the numbers would be great and tricks on installation. More on the trans cooler and if elimanating the stock version and going directly from hte trans to the cooler. Are there special hoses required?

Thanks to all

Acy540

The part number for the new thermostat was HL3Z-8575-B. A youtube video that I found in the internet is https://youtu.be/S0Kabry6I3M?si=3lGwi_vKNYOg-Qa6. You have to remove the air intake to get access. Whole thing takes about 15-30 minutes.

 

[acy540]

 

[Password]

It's worth changing the thermostat even if it's not the culprit. I don't know what my engine temps were, but the trans would get to 205-212 driving on the highway 70+mph. It jumped to 255 one day. Changed the t-stat and temps haven't hit over 200 under the same conditions.

 

[SyndicateZ]

Doe the t-stat on the engine also control transmission temps too?

 

[JasonH]

Doe the t-stat on the engine also control transmission temps too?

My recollection is that on the 4th gens, the transmission cooler has a heat exchanger that dumps heat from the transmission into the engine coolant. I'm sure someone will provide a correction if that wrong.

 

[slow3v]

My recollection is that on the 4th gens, the transmission cooler has a heat exchanger that dumps heat from the transmission into the engine coolant. I'm sure someone will provide a correction if that wrong.

This is correct.

 

[gslader]

I’ve got a 2020 Expedition and have replaced the OEM thermostat with an aftermarket (195 degree open) version. I am still getting elevated temperatures when accelerating (typically when I accelerate above 70 mph). The temperature will jump (very quickly) up to the low-to-mid 230s then drop back down typically in about 5-10 seconds if I stop accelerating. I’m not losing any coolant and coolant levels are normal. I don’t see any codes getting thrown so I’m at a bit of a loss as to what could be causing this. Maybe a water pump that is going bad?

 

[dlcorbett]

Your using aftermarket, but is it for 2020 expy or 2022?

 

[gslader]

I believe it is for a 2020. Here is the part that I installed:

https://www.oreillyauto.com/detail/c/plus/murray-plus-195-degree-thermostat/mcs1/65595/v/a/148798/automotive-suv-2020-ford-expedition

 

[dlcorbett]

Ford changed the thermostat for thw 2022 truck, so the one you had installed probably would have the same problems as the one you replaced. I changed out my navs thermostat to a 2022 version and it never went over 195 degrees after half days worth of driving through mountains.

 

[gslader]

Ahh. . . Very elucidating. I had assumed that the aftermarket thermostats incorporated the post-2022 redesign, but that was likely a faulty assumption. I’ll pick-up a post 2022 thermostat and try again. Thanks for the response!

 

[gslader]

So I replaced with thermostat (again) with this 2022 aftermarket part (https://www.oreillyauto.com/detail/c/plus/murray-plus-190-degree-thermostat/mcs1/65590) and I am still running into overheating issues. It only occurs when we have a car full of passengers and at freeway speeds. This is occurring on flat highways at speeds of +70mph and with an ambient temperature of ~55 degrees F. The coolant level is staying consistent and I’m not getting any codes and the radiator is unobstructed. I am at a bit of a loss on this one. Any other suggestions?