Towing temperature report: Scangauge II

Certainly this isn't an extreme towing situation, but I found it rather illuminating to what I could expect if I were towing a heavier load, in moderate summer temps (mid to upper 80's)

Mine is a 2011 SR5 DCSB, 4x4, 4L V6/5spd automatic with towing package and no upgrades. I recently installed a Scangauge II and did the programming to monitor transmission fluid temps in the pan and at the torque converter, and I also had coolant temps monitored. Today the load was an 18ft dovetail flatbed (1800 lb. empty weight), with a 2012 Honda Civic (2850 lb) loaded on it, for a total of 4650 lb. It was an interstate trip almost all the way, about 165 miles. All driving was done in 4th, between 65-70 mph. Outside temperature was around 82 (radio weather report). Sunny and dry, moderate humidity.

The engine coolant stayed between 186-188 all the time, except on a couple of longer hills, where it climbed briefly to 196, but never did it go any higher than that. TF1 (pan temp) got no higher than 178, and that on the same long hill, but stayed mostly between 164-170. TF2 (torque converter) varied quite a bit and rose faster than TF1 under the same loads, as expected. The highest I saw TF2 was 190, on a single pull when the tranny downshifted to 3rd as I accelerated to 70 mph after slowing for traffic. Once at speed, it rapidly dropped back to 170, same as TF1 was at.

The interstate along this route has lots of rolling hills, 1/4 to 3/4 miles long grades of what is typical to western NC foothills.

Given the temps I saw, I think I could reasonably expect to haul another 1000 -1500 pounds without taxing the cooling.

 

Those aren't bad temps at all. I get higher on the beach.