Jozef Zoldos
Well-Known Member
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.
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.
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