Help! Overheating on a Road Trip :/

[madrose124]

There was a case of overheating couple of years ago and turned out to be bad radiator.

Other things to check first are the grille shutters (stuck closed) or faulty radiator fan.

This could very well be it. Now that the sun has set, our temps are doing much better and we are back to being able to go 75mph. Transmission staying at 208-210 with coolant sometime spiking to 232 on a hill. Whereas during the day in the heat we could barely climb a slight grade at 61mph without approaching 225/245 respectively.

 

[Dice Roll]

Are you sure it was purged well enough? These things have a second heater core for the rear hvac. There is some big song and dance of reving the engine with the heat on etc to get all the air out.

The upgraded part is a rt1258, ford has some sort of convoluted part number that is goes by as well. I do think the newer one is plastic instead of brass.

The other suggestions to look at are excellent ideas also.

The rt1258 solved my hot running 2019 that had been hot since new and it wasn’t apparent. I don’t think it ever worked right and it was starting to spike temps ever now and then around 30k miles. I went from 205 trans temp when driving in town and 212-215 towing to 180-190 all the time and maybe 192-195 towing.

 

[Boosted]

Are you sure it was purged well enough? These things have a second heater core for the rear hvac. There is some big song and dance of reving the engine with the heat on etc to get all the air out.

The upgraded part is a rt1258, ford has some sort of convoluted part number that is goes by as well. I do think the newer one is plastic instead of brass.

The other suggestions to look at are excellent ideas also.

The rt1258 solved my hot running 2019 that had been hot since new and it wasn’t apparent. I don’t think it ever worked right and it was starting to spike temps ever now and then around 30k miles. I went from 205 trans temp when driving in town and 212-215 towing to 180-190 all the time and maybe 192-195 towing.

Can you tell me what your coolant temps were? I have been looking for a concise reference for this and I think you have the data.

Original Thermostat RT1252:
Coolant Temperature:
Transmission Temperatrue Normal:
Transmission Temperature Towing:

Revised RT1250 Thermostat:
Coolant Temperature:
Transmission Temperatrue Normal:
Transmission Temperature Towing:

 

[Dice Roll]

I never saw the coolant temps. Think the gauge spiked the one time in the month before I changed it. The trans temps are what I posted. That is what I normally drive with up on the dash. Best proxy I know. Wish they gave us the coolant number. I think forscan can add it, but I lack the dedication or real desire to fool with that. Ditching the double honk is very tempting though.

All I can say is, everyone should get the stat updated asap. At this point it’s reasonable to change the coolant anyway based on age. For the earliest trucks anyway.

 

[madrose124]

Interestingly, once the ambient temps went under 95 our car did just fine going 75mph. We are going to attempt a 170 SPD thermostat to see if that makes a difference and possibly upgrade the radiator. It seems like an efficiency of the system issue. Probably going to replace parts as much as we can ourselves to eliminate the source of the problem. I’d like to be able to drive 75 in the summer heat since we live in Louisiana.