Engine temp spikes on highway

keny01998

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For a long trip over 10 hours, I usually got engine temp over 230 for 1 minute or 2, sometimes it went up to 235 but went away. My trans temp went up to 217-220.
 

2020ExpyPlatinum

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I would guess there is air trapped in the system possibly. Some vehicles have a very specific bleed procedure to get the air out.

If it is not air in the system is it possible the automatic louvers are acting up behind the front grill? I know on our expedition it has computer controlled louvers that open or close depending on the vehicle temperature.
 

byathread

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My 2019 will, at certain points, show the coolant temp when it reaches that threshold, usually noticed it after heat soaking events like max throttle while towing or driving the piss out of it (hard acceleration uphill on the highway, etc.). It shows upwards of 238 or so and then recedes, basically due to the thermostat opening lag and coolant flows, is what I always thought... Normal, no leaks I'm aware of and has been doing that since new. Currently at about 46K... Even at 240-242 briefly, it's probably fine/not cooking it/within tolerance. I remember seeing 238 or 240 once and the gauge turned amber then went right back to blue. Unless there is clear evidence of a leak, then, just drive it is my $0.02...
 

Artie

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Reading through this thread I’m wondering if not purging the cooking system could have caused my transmission temperature spike. Does anyone know if the transmission has its own completely separate cooler or does it share with the radiator?
 

wakeboarder

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Reading through this thread I’m wondering if not purging the cooking system could have caused my transmission temperature spike. Does anyone know if the transmission has its own completely separate cooler or does it share with the radiator?
It uses coolant from the engine’s radiator. There is a heat exchanger under the transmission.
 

Soliyou

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These engines can be difficult to bleed properly. A trapped air bubble may cause a spike in temperature and high pressure that can lead to leaks.

The shop manual only recommends using the vacuum fill procedure for the coolant.

The old style thermostat is also known to fail and cause slight overheat after coolant change.
 

wakeboarder

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These engines can be difficult to bleed properly. A trapped air bubble may cause a spike in temperature and high pressure that can lead to leaks.

The shop manual only recommends using the vacuum fill procedure for the coolant.

The old style thermostat is also known to fail and cause slight overheat after coolant change.
My shop manual has both vacuum fill and without a vacuum fill. I followed the manual with the front uphill and on ramps. I also squeezed the coolant hoses. I have towed since then and haven’t seen any bleed issue. If I remember correctly, the bleed procedure takes 1/2 hour to 45 minutes.
 

Soliyou

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My shop manual has both vacuum fill and without a vacuum fill. I followed the manual with the front uphill and on ramps. I also squeezed the coolant hoses. I have towed since then and haven’t seen any bleed issue. If I remember correctly, the bleed procedure takes 1/2 hour to 45 minutes.
Honestly I didn’t see the other procedure in the manual, but the manual is huge!

I am referring to the flush instructions shown below:

22284146-FD03-4921-A074-B2BFEC672E38.jpeg
 
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