2007 GMC Yukon XL Denali 6.2 Overheating at a stand still

[THarber]

That's pretty close to where it needs to be (+-210). Changing the thermostat will do no good unless you program the computer to turn the fans on sooner. That can be accomplished via HP Tuners or other paid programs. Make sure however, that you have purged all the air out of the system. These trucks are notorious for getting air locked. The easiest way to do so is to loosen the upper radiator hose at the block and let any air out or use a pressurized system to refill coolant.

 

[gooffeyguy]

I know normal temp is about 210, but mine always runs at 197/198 and sometimes while idling in the summer will go up to 205. This is viewing the temp with the Torque Pro app or on the DIC using the AutoSync add on. I don't think I've ever had it get to 210, even in summer, full of people, driving through the Smokey Mountains

 

[Sangster]

I've been having this same issue with my 2013 Denali. Replaced the radiator with an all aluminum when the stock radiator plastic ends cracked. Still kept getting warm. Replaced water pump with new OEM pump. Replaced thermostat with OEM. Replaced any sketchy hoses. 7/9 blade e-fans. I have no leaks, and expansion tank is full. Using Torque Pro app, at idle with AC off, temp will creep up to 225 and then the fan will kick up to high. Temp will drop down to 215 and the fan will kick down to low. Temp will then creep back up to 225....fan goes back to high....temp goes down to 215.....rinse and repeat. With AC on, fan kicks to high almost right away and stays on. Temp depends on if I'm in stop and go (gets warm) or highway (stays 200-210). I also have a Trucool 40k trans cooler mounted in front of the AC condensor/radiator.

I'm wondering if the trans cooler (trans will go up to 170ish when the engine coolant is up at 220+ but generally stays in the 150-160 range) is blocking air flow through the AC condensor/radiator enough to cause it to run warm?

What temp SHOULD the fans kick to High at? I'm Blackbear tuned and Justin says it's programmed to kick to HIGH fan "10-15 degrees cooler than stock", but I'm not buying that. If that were true, then @ stock, the fan wouldn't go to high until 235 and that's way too high.

#stumped

 

[swathdiver]

I've been having this same issue with my 2013 Denali. Replaced the radiator with an all aluminum when the stock radiator plastic ends cracked. Still kept getting warm. Replaced water pump with new OEM pump. Replaced thermostat with OEM. Replaced any sketchy hoses. 7/9 blade e-fans. I have no leaks, and expansion tank is full. Using Torque Pro app, at idle with AC off, temp will creep up to 225 and then the fan will kick up to high. Temp will drop down to 215 and the fan will kick down to low. Temp will then creep back up to 225....fan goes back to high....temp goes down to 215.....rinse and repeat. With AC on, fan kicks to high almost right away and stays on. Temp depends on if I'm in stop and go (gets warm) or highway (stays 200-210). I also have a Trucool 40k trans cooler mounted in front of the AC condensor/radiator.

I'm wondering if the trans cooler (trans will go up to 170ish when the engine coolant is up at 220+ but generally stays in the 150-160 range) is blocking air flow through the AC condensor/radiator enough to cause it to run warm?

What temp SHOULD the fans kick to High at? I'm Blackbear tuned and Justin says it's programmed to kick to HIGH fan "10-15 degrees cooler than stock", but I'm not buying that. If that were true, then @ stock, the fan wouldn't go to high until 235 and that's way too high.

#stumped

What brand of radiator? Is there a restrictor in the radiator or line that goes to the expansion tank? Some radiators are missing this feature which causes temperature issues though I forget which way.

Have you tested all three relays? I have the stock transmission cooler and mine has similar temps as yours, might be something going on inside the trans? Is the converter still locking up?

Are you sure there are no air pockets in the system?

 

[Sangster]

What brand of radiator? Is there a restrictor in the radiator or line that goes to the expansion tank? Some radiators are missing this feature which causes temperature issues though I forget which way.

Have you tested all three relays? I have the stock transmission cooler and mine has similar temps as yours, might be something going on inside the trans? Is the converter still locking up?

Are you sure there are no air pockets in the system?

This radiator: https://www.amazon.com/gp/product/B01LY5ZSB4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Not sure about a restrictor, but I was having overheating issues before I replaced the radiator.

Which relays are you referring to?

My stock radiator temps were about 30-40 degrees warmer than they are now with the TruCool 40k. That seems in line with other testimonials I've seen. I'm happy with the trans temps. Converter locks up fine, what would make you think it wouldn't? I'm not experiencing transmission heat issues, even before the aftermarket cooler.

Pretty sure there aren't any air pockets, it's been a good 15k-20k miles since I swapped everything out.

 

[swathdiver]

This radiator: https://www.amazon.com/gp/product/B01LY5ZSB4/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Not sure about a restrictor, but I was having overheating issues before I replaced the radiator.

Which relays are you referring to?

My stock radiator temps were about 30-40 degrees warmer than they are now with the TruCool 40k. That seems in line with other testimonials I've seen. I'm happy with the trans temps. Converter locks up fine, what would make you think it wouldn't? I'm not experiencing transmission heat issues, even before the aftermarket cooler.

Pretty sure there aren't any air pockets, it's been a good 15k-20k miles since I swapped everything out.

The fans are operated by three relays to either have them run at low speed or high speed.

I am also in Florida and my temps are about the same with the stock transmission coolers. Have you cleaned the fins on the condenser or changed grills or... Wait a sec, what are the condition of the baffles, those tar paper like pieces that go on either side of the radiator and one underneath? When these deteriorate and fall away, a lot of air then makes its way around and not through the radiator.

Here's a pic from the internet:



The one to our right is intact and in place. The one on the left has fallen out of place some. Mine were falling apart so I replaced them when we did the bumper cover.

 

[Sangster]

Both of my baffles are flimsy/torn and not doing anything. I think they both are flimsy enough to have fallen down.

But could that be enough to cause it to run too warm? The "fins" on the radiator (new) and trans cooler (new) are clean. The AC condenser looks good too.

 

[swathdiver]

Both of my baffles are flimsy/torn and not doing anything. I think they both are flimsy enough to have fallen down.

But could that be enough to cause it to run too warm? The "fins" on the radiator (new) and trans cooler (new) are clean. The AC condenser looks good too.

If they are not doing what they are supposed to do, yes, the motor will run warmer as too much air is getting around the radiator and not through it to cool.

 

[Sangster]

I'm not convinced they would help for my specific issue. I don't have any cooling issues at highway speeds, which tells me that there is plenty of airflow through the radiator. When at slow speeds and relying on the fans, the fans PULL air through the radiator from inside the fan shroud.....so those baffles aren't doing anything to help with that. The baffles are to direct air through the radiator at speeds where the fans are turned off. They don't do anything at speeds that use the fans for airflow. I don't have any cooling issues then....only at slow speeds and while stopped (idle).

 

[Fless]

Open baffles could allow engine heat (pushed by the fans) to recirc to the front of the radiator at idle or low speeds. What's to be lost by making them whole again? If nothing else it could disprove my statement above. I'd be curious.