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.
2020 Expy Overheating at Highway speeds.
- Thread starter Jozef Zoldos
- Start date
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SyndicateZ
Full Access Members
Doe the t-stat on the engine also control transmission temps too?
JasonH
Full Access Members
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
Member
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?
gslader
Member
I believe it is for a 2020. Here is the part that I installed:
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
Member
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
Member
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?
