2010 Yukon Denali Overheating when Towing

If your current radiator is over 10 yr old it would be wise to replace it with the surrounding hoses and heater hoses.

The radiators get clogged up with a really fine, powdery dust that accumulates like paint. After a while it restricts the thermal cooling effect when it needs it most. You can remove it and have it hot tanked but it’d be better to just replace it since you’re towing.

Marky Dissod said:

Actually, this is nearly conclusive evidence that the engine had an electrical fan conversion.

Click to expand...

In a 2010 Yukon Denali?

Actually, this is nearly conclusive evidence that the engine had the water pump replaced at some point

Tim907356 said:

In addition to the electric fans, should there/could there also be a clutch fan? The hub on the motor has threads for one, but it’s not there.

Click to expand...

Do you mean the hub on the water pump?

gooffeyguy said:

In a 2010 Yukon Denali?

Actually, this is nearly conclusive evidence that the engine had the water pump replaced at some point

Click to expand...

I'm under the impression that the OE pumps still have the threads for the clutch fans. RockAuto shows GM water pumps with them for this year. Seems like I remember @iamdub dressing up his threads somehow.

Fless said:

I'm under the impression that the OE pumps still have the threads for the clutch fans. RockAuto shows GM water pumps with them for this year. Seems like I remember @iamdub dressing up his threads somehow.

Click to expand...

True, my 2012 has them. I thought it didn't but I just went and looked.

gooffeyguy said:

In a 2010 Yukon Denali?
Actually, this is nearly conclusive evidence that the engine had the water pump replaced at some point.

Click to expand...

Touche. Forgot about that it's a 2010.

Tim907356 said:

Mine is a '2500', 6.2L Denali. I'm due an oil change so I'll look for the block off plate. that sounds like a good option!!...
Edit: KC4, dangit, it's already there1

Click to expand...

2500 short wheelbase? Um, no.

gooffeyguy said:

In a 2010 Yukon Denali?

Actually, this is nearly conclusive evidence that the engine had the water pump replaced at some point

Click to expand...

My 09 Sierra Denali has efans and a threaded water pump hub, and it rolled out of the factory like that.

I hit 235° when towing in the Rockies with my 8600-lb trailer. It doesn't bother me a bit. I let the factory cooling system do its thing.

intheburbs said:

My 09 Sierra Denali has efans and a threaded water pump hub, and it rolled out of the factory like that.

Click to expand...

Yeah, I posted a bit later that mine does too after going out and looking at it, lol

For some reason I kept picturing in my head that it didn't, and the hub only stuck out of the pulley a tiny bit. That's actually on the 2002 Mustang 4.6. I have too many vehicles here, I'm starting to confuse their parts, lol

Kind of like kids names as you get older

My true GM replacement pump on mine from a few years ago has threads on
the hub as well. I just left the plastic protector piece on it so I won't cut
myself on it.
The E fan strategies on these gen 4 gm900's kinda suck in my opinion.
I'm sure it has to do with cafe or epa crap.
At highway speeds the fans won't come on at all. Thats why when you slow
down towing to about 45-50 the engine cools off.
I've reset my override temp to see if I can get it to trigger the fans to ON
but haven't towed hard in the heat yet to test it out.
My advice to an owner of a 14 year old tow vehicle is to at least get
a new OE radiator (as they catch lots of unseen crap as mentioned) or upgrade
to an all aluminum aftermarket one if towing heavy lots

Foggy said:

The E fan strategies on these gen 4 gm900's kinda suck in my opinion. I'm sure it has to do with CAFE MpG or EPA crap.

Click to expand...

Yep. Motor oil, ATF, & gear oil all have a bit less friction @ 221F than they do @ 203F.
GM would rather you get 1 or 2 more MpG, than your under the hood stuff last longer.

Foggy said:

At highway speeds the fans won't come on at all.
That's why when you slow down towing to about 45-50MpH the engine cools off.

Click to expand...

Somewhere between 45MpH & 50MpH, the fans can no longer outperform
the passive headwind of forward motion shoving air through the radiator.
So it becomes pointless to waste energy.
(I forget at which road speed having the fans 'on' actually hinders airflow ...)