Engine getting hot towing

[Bonebad1]

2012 Yukon Denali xl Tow package. 150000 miles. Tranny flushed last month and diff and transfer case. Coolant 3 years old.
I tow a 5500lb camper with 800 lbs of passengers and plus all our stuff so probably around 7000 to 7500 lbs. We have a wdh all set up by the camper place we bought.our camper from. Last year the transmission would get warm, around 220 so I added a trucool 40k. Now the engine gets hot, around 230 when I turn the heater on to cool it off.
I am only going 50-60mph. What can I do to get the engine temps lower

 

[avalonandl]

Flush radiator, clean out the fins with a hose, check your water pump as LS water pumps lose their effectiveness often.

 

[wsteele]

2012 Yukon Denali xl Tow package. 150000 miles. Tranny flushed last month and diff and transfer case. Coolant 3 years old.
I tow a 5500lb camper with 800 lbs of passengers and plus all our stuff so probably around 7000 to 7500 lbs. We have a wdh all set up by the camper place we bought.our camper from. Last year the transmission would get warm, around 220 so I added a trucool 40k. Now the engine gets hot, around 230 when I turn the heater on to cool it off.
I am only going 50-60mph. What can I do to get the engine temps lower

There is a very informational thread started by @Geotrash on this very subject. I would give it a read. At a minimum, it will give you a good basis of understanding of the dynamics involved and alternatives.

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

Hi All, the 2012 XL Denali is a towing beast, but after the cam upgrade, new HD torque converter, and adding the Tru-Cool 40K in front of the radiator, the engine itself is running warm now that we're getting into spring. Hauled our 6500 lb camper down to Virginia Beach this weekend in 83º...

www.tahoeyukonforum.com

 

[Foggy]

Your TrueCool is probably blocking some air flow to the radiator itself..
You may need to replace & upgrade your radiator.. Depending on how often you tow
and the weather conditions
Make sure you are towing and being smart about the transmission gear selection..
If you are only going about 55-60, then 4th gear would be the one you want...
5th and 6th are overdrive ratios and will tend to get the trans warm under heavy loads

You could also try the simple things like new coolant, water pump first..
For the summer, try a 30% dexcool/ 70% distilled water mixture with an additive
like water wetter coolant additive and see what happens

 

[swathdiver]

2012 Yukon Denali xl Tow package. 150000 miles. Tranny flushed last month and diff and transfer case. Coolant 3 years old.
I tow a 5500lb camper with 800 lbs of passengers and plus all our stuff so probably around 7000 to 7500 lbs. We have a wdh all set up by the camper place we bought.our camper from. Last year the transmission would get warm, around 220 so I added a trucool 40k. Now the engine gets hot, around 230 when I turn the heater on to cool it off.
I am only going 50-60mph. What can I do to get the engine temps lower

Make sure the mix of Dexcool to water is proper, if there's more dexcool than water its going to run at a higher temperature. 50/50 is what's called for, some do 60/40 for a little more cooling.

Transfer as much stuff to the trailer as possible.

Does yours also have the engine oil cooler?

 

[Bonebad1]

I'll have to check my dexcool ratio. I had it flushed a while back and haven't checked it since. It does have the oil cooler. Should I just change the water pump or is there a way to see if it is pumping good enough? .l

 

[Foggy]

I would change the water pump at that mileage/age.. Use a GM or ACdelco branded
pump if at all possible. And just replace all the dexcool coolant with 50/50 distilled water
or buy it premixed. Thermostat would be on my list as well while you are there...
I "think" my new GM pump that I bought last year from RockAuto came with a new
gm thermostat - much better build quality than the aftermarket parts store Tstats
and it's worth about $35 so you can justify the extra cost that way too

 

[Foggy]

For my application ACDELCO 251713 this is the part #.. Yours may be different. But this is
the one that has the thermostat already installed, so you get a new high quality Tstat too

 

[RED TAHOE LS]

180 degree thermostat....JMHO.

 

[Geotrash]

2012 Yukon Denali xl Tow package. 150000 miles. Tranny flushed last month and diff and transfer case. Coolant 3 years old.
I tow a 5500lb camper with 800 lbs of passengers and plus all our stuff so probably around 7000 to 7500 lbs. We have a wdh all set up by the camper place we bought.our camper from. Last year the transmission would get warm, around 220 so I added a trucool 40k. Now the engine gets hot, around 230 when I turn the heater on to cool it off.
I am only going 50-60mph. What can I do to get the engine temps lower

What you’re describing is normal coolant temp behavior when towing with the Trucool 40k. I’ve owned two of them on two different Yukon XL Denali’s and had the identical behavior to what you describe on both. I even upgraded to a cold case radiator on one and while it helped, it didn’t eliminate the problem. I wouldn’t waste time or money replacing water pumps or anything else. Just my opinion. The solution is to either relocate the tru cool to below the front bumper or mount a fan-forced one like the Derale below the bumper.

Also 220°F is well within the normal trans temp range on the 6L80E. You’re good to 265° with the Dexron VI fluid in these.

 

[gooffeyguy]

Have any of you towed with the OE auxillary trans cooler setup and what were the engine/trans Temps?

 

[wsteele]

Have any of you towed with the OE auxillary trans cooler setup and what were the engine/trans Temps?

I have and towed a 5000lb enclosed trailer a lot early on in my trucks life. The trailer was pretty low profile and pretty aero as big old trailers go, most of the towing was summer months. I rarely saw 230 degrees, even on hot days through mtn country with extremes being as high as 240 for short periods on pulls up into the Tehachapies in summer temps.

The thing is, I sometimes think my transmission temp gauge might have been off, as my tranny lasted about 76K miles and needed replacement. Reading the reports of what others have seen in the "Keeping coolant and transmission temps ..." thread, it really makes me wonder about that temp gauge.

Also, mine is a 4 speed and I was changing fluid and filters every 50K.

 

[1BADI5]

With my TruCool 40K my engine temps stay between 197-203* even when I'm out hoon'ing the hell out of it AND I have a stall converter.

What kind of spacing between the trans cool and condenser? What mounts are you using?

The highest trans temp I have had was 154* (Those readings came from the OEM and aftermarket gauge)

 

[Geotrash]

With my TruCool 40K my engine temps stay between 197-203* even when I'm out hoon'ing the hell out of it AND I have a stall converter.

What kind of spacing between the trans cool and condenser? What mounts are you using?

The highest trans temp I have had was 154* (Those readings came from the OEM and aftermarket gauge)

But are you towing heavy with it? That’s the only circumstance where heat has been an issue with the 40k.

 

[Bonebad1]

With my TruCool 40K my engine temps stay between 197-203* even when I'm out hoon'ing the hell out of it AND I have a stall converter.

What kind of spacing between the trans cool and condenser? What mounts are you using?

The highest trans temp I have had was 154* (Those readings came from the OEM and aftermarket gauge)

I have it mounted in front where the aux cooler was. It only gets hot when towing

 

[Bonebad1]

I did tow this camper before the trucool. Trans temps were getting high, I think around 220-240. but the engine temps were good. Now after the trucool install trans temps havent gone above 175 but the engine temps are up. I am pretty sure the trucool is blocking too much airflow. I can try the water pump, flush, water wetter. but wont really know until I tow again which may not happen any more this year with school starting up

 

[RedInCo]

I'll add my experience in response to gooffeguy. I have a 2010 Yukon Denali AWD (6.2L, 6 speed, short wheelbase, 140K, all stock with the factory maxtow package tranny cooler). I tow a 6900 pound travel trailer, often in Colorado. When not towing, engine temp stays at 210, tranny will get to 160-180. When towing on the flat, engine stays at 210, tranny is about 100 degrees above ambient. Add mild hills, the engine get to 220 or so on the climbs, tranny will go up to 215-225.

On big climbs, like I-70 at the continental divide, the engine will get up to 235, then quickly drop down to 210 when the fans kick on. This will repeat every few minutes. The tranny temp will climb steadily without regard for what the fans and the engine temp are doing. I aim to keep the tranny from getting above 250 for any length of time. If the tranny gets above 240 and I have a lot of climb to go, I chicken out and pull off and let it idle for a while.

Two weeks ago I camped for the night at Copper Mountain. Hitched up the trailer in the morning, jumped on I-70 going east. At the Silverthorne exit the tranny temp was 150. I cruised to the continental divide summit without stopping (doing about 45) and the tranny temp just hit 250 as I entered the tunnel.

I just bought a Tech 2. Does that allow me to turn the fans on high when underway? Would it be smart to have the copilot force the fans on during a big climb?

 

[Geotrash]

I'll add my experience in response to gooffeguy. I have a 2010 Yukon Denali AWD (6.2L, 6 speed, short wheelbase, 140K, all stock with the factory maxtow package tranny cooler). I tow a 6900 pound travel trailer, often in Colorado. When not towing, engine temp stays at 210, tranny will get to 160-180. When towing on the flat, engine stays at 210, tranny is about 100 degrees above ambient. Add mild hills, the engine get to 220 or so on the climbs, tranny will go up to 215-225.

On big climbs, like I-70 at the continental divide, the engine will get up to 235, then quickly drop down to 210 when the fans kick on. This will repeat every few minutes. The tranny temp will climb steadily without regard for what the fans and the engine temp are doing. I aim to keep the tranny from getting above 250 for any length of time. If the tranny gets above 240 and I have a lot of climb to go, I chicken out and pull off and let it idle for a while.

Two weeks ago I camped for the night at Copper Mountain. Hitched up the trailer in the morning, jumped on I-70 going east. At the Silverthorne exit the tranny temp was 150. I cruised to the continental divide summit without stopping (doing about 45) and the tranny temp just hit 250 as I entered the tunnel.

I just bought a Tech 2. Does that allow me to turn the fans on high when underway? Would it be smart to have the copilot force the fans on during a big climb?

Great info. Thanks for the data points. No, I don’t believe the Tech2 will do that. And even if it could, it would be a huge pita and safety issue to try to do it while driving. You’d be better off having a tuner change the fan trigger points.