Keeping coolant and transmission temps under control when towing in the summer heat

[gooffeyguy]

I did some moderate hills yesterday pulling my 5000lb camper and my engine temp reached 237 and it was about 100 outside. My trans temp reached a max of 208 so I'm not worried about that, just my engine temp. The rest of the trip I ran with no AC and it peaked around 220. I have a Derale transmission cooler and my next mod might be to relocate it to the lower intake. But what I don't understand is that pulling the camper in traffic or around town in stop and go is fine and the temps stay normal, but on the highway when it should be getting tons of airflow is when I seem to have issues? Here's a screenshot of my numbers.

Are the air deflector pieces on the sides of the radiator (don't remember the technical name for them) still there and intact?

 

[Cincikid]

Are the air deflector pieces on the sides of the radiator (don't remember the technical name for them) still there and intact?

Yes, I fashioned some of my own, after the OE ones disintegrated, from a yard sign just like another member here.

 

[Doubeleive]

Are the air deflector pieces on the sides of the radiator (don't remember the technical name for them) still there and intact?

my yukon doesn't have any and no signs of it ever having any

 

[gooffeyguy]

my yukon doesn't have any and no signs of it ever having any

Original owner?

 

[Doubeleive]

Original owner?

no I am the 2nd owner it was owned by some corporation, I highly doubt they ever did anything to it, it was stock, when I took the front bumper cover off to modify and move the tru cool to the lower grill I noticed it has nothing there on the side's of the radiator just open spaces, maybe there just completed rotted and gone completely?

 

[Geotrash]

I did some moderate hills yesterday pulling my 5000lb camper and my engine temp reached 237 and it was about 100 outside. My trans temp reached a max of 208 so I'm not worried about that, just my engine temp. The rest of the trip I ran with no AC and it peaked around 220. I have a Derale transmission cooler and my next mod might be to relocate it to the lower intake. But what I don't understand is that pulling the camper in traffic or around town in stop and go is fine and the temps stay normal, but on the highway when it should be getting tons of airflow is when I seem to have issues? Here's a screenshot of my numbers.

Yep, that’s how mine is too. Gotta remember that the engine isn’t making much power at idle but on the highway pulling a camper, it is. The factory radiator is undersized for the 6.2 towing, imho.

 

[Cincikid]

Yep, that’s how mine is too. Gotta remember that the engine isn’t making much power at idle but on the highway pulling a camper, it is. The factory radiator is undersized for the 6.2 towing, imho.

Seems like it should be similar spinning at 3000 RPMs on the highway versus doing 35 miles per hour. At least for the engine's sake.

 

[Geotrash]

Think of it this way,

Seems like it should be similar spinning at 3000 RPMs on the highway versus doing 35 miles per hour. At least for the engine's sake.

Think of it this way, cooling capacity needed is a function of BTUs per hour in heat output, which is a function of the horsepower being produced. At 300 hp output, the engine will produce about 760,000 BTUs per hour, whereas at 40 hp, it will only put out 100,000 BTUs per hour. That’s a significant difference and cooling capacity needed.

 

[Geotrash]

Enjoying the fruits of all of that work! Colter Bay RV campground, Grand Teton National Park.

 

[Cincikid]

Do you guys know is the electric fans turn off over a certain speed?