2011 Yukon XL Denali 6.2L cooling trouble while towing

950410 said:

Is the transmission hunting for gears during the climb? Is the torque converter unlocking to make the pull? I would probably put the shifter in manual mode and hold the trans in 4th or 5th gear (if it's a 6-speed) and make sure the converter is staying locked. Constant shifting and an unlocked converter creates a lot of heat.

How long does this hill take the climb? Really I wouldn't worry too much about the trans temp rising on a hill, as that's common. As long as it's not rising excessively or stays that hot for too terribly long. Just my two cents.

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I do put the shifter in manual and make sure there isn't a lot of shifting during the climb. One of the hills is about 15 miles and an elevation gain of about 3000'. Another is about 40 miles and an elevation gain of about 3000'. The 40 mile climb seems to give me more trouble than the shorter, steeper climb. I believe it has to do with speed and duration. It's on an interstate and I try to keep the speed above 55 if I can. There is a climbing lane for a portion where I am not as concerned with speed and I dropped down to about 45 for a bit. On the 15 mile climb, I maintain speed between 30-40 mph and the temps are easier to manage.
I don't have an issue with Trans temp. Trans temp never gets above 210 since I installed the cooler. My concern was with engine coolant temps. I did read in the owner's manual that it is normal for temps to reach 250 dog when towing or climbing. This eases my mind that there isn't something internally wrong that is causing the heat. I will likely look for a larger radiator and see if that helps. Other than that, it looks like I'll just have to get used to it. I guess my expectation was not in line with what reality is, when towing. I assumed that the larger, more powerful motor would handle my trailer with ease. That isn't the case.

Thanks for the input.

Mike

Does anybody have any recommendations for a larger OEM or aftermarket radiator?

I gotcha. Yeah, GM coolant systems lack a little giving their tow rating, IMO. I would agree there's nothing wrong with your ride.

Sorry I don't have a upgraded radiator recommendation. Good luck!


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I know one thing alot of people neglect to do is to wash and flush the outside of their radiators. Alot of dirt and debris can collect inbetween the fins over the years. Washing this thoroughly can help improve the radiators performance. That being said your temps seem right in line with what my denali shows when towing our 30' camper. And we dont have very many mountains or hills in michigan. My trans temps are usually around 200-220 and the engine temp is always 210-220.

My Escalade tows my boat to arizona from so cal, with the trucool 40k trans temps have not exceeded 200deg towing in 115 degree heat, i also plan to run a low temp 160 degree thermostat instead of the factory 180, and have the computer programmed for the fans to come on sooner, my boat weighs roughly 5500lbs


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I live in Colorado and have a 5000 pound trailer we tow at high altitude. I had the same concerns after taking our camper out for the first time and the tranny hit 230. I installed the same cooler you did and now the tranny stays nice and cool. A couple of weekends ago we took highway 50 over Monarch pass (summit over 11,000 feet). I am running with the 2010 Yukon 5.3 and HD towing package. We did 40 all the way up the pass in 2nd gear at about 3500 RPMs. The transmissions highest temp at the top of the pass was 205. Other than the mountain passes the vehicle does great, but at the top of the pass the engine temp was 235. I realize I could have gone slower and stayed cooler, but where's the fun in that? The second I reached the top and backed off the engine immediately cooled down. I know the engine temp didn't get too bad, but I am considering installing a remote engine oil cooler with a fan. Next mountain pass all I have to do is flip the switch and the engine oil cooler should be plenty to cool the engine enough to barrel up that hill at the posted speed limits.

Thanks for all the help, guys. Seems like I was overly concerned about an issue that is pretty common. I'll just make sure to thoroughly clean my radiator and take it easy.

Just had a transmission cooler installed on mine. Really helped out there. Used the True Cool brand. I will have to try spraying down my stock radiator also.

Is there anything else to do to keep the temp lower?

I was also concerned about overheating while towing a 30ft travel trailer with my 11 Denali, 6.2l. Temp shot up to 230 on tranny with standard equipment I added an additional tranny oil cooler and tranny temp didn't go above 201 while going up hill, but my temp ranged from normal of 210 to 230. I have now bought a Griffin three row engine cooler and will haul at the end of May. I'll keep you posted as I travel from Central Texas to Yuma, AZ

Do you know the part number of the Griffin radiator?

Was there anything else that you had to do to fit the radiator?

Sorry so many questions started having temperature problems while towing with my 2010 XL Denali.

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