Heatin/overheating??!

[Tim907356]

So, were taking our first weekend getaway to the nc mountains, near Cherokee. We’re pulling our, let’s say, 4500# travel trailer. Going up hills, even modest ones, I see the temp gauge rise to as much as ~240deg. or so. I’ve never seen it move from 210 before,but haven’t loaded it this much either.
Comparing to my old 04 Yukon xl, its temp never budged: I could be going up a hill floored at 40mph. with the trailer, and it wouldn’t move 1deg. from 210. I checked coolant, and it’s topped off. The temp drops to normal going downhills.
So, is this behavior normal? It would seem a long really tough set of hills might sideline a trip, or break something! Anybody have this issue, and hopefully a solution??
THANKS!!

 

[Doubeleive]

possible fixes:
chemical flush, new radiator & higher wattage fans
the rpo code k5l is the heavy duty cooling package
a tru-cool 4k transmission cooler helps also
beyond that there really isn't much else you could do besides change the gearing to make it not work as hard

if your radiator is 5 years old more I would consider replacing it, it can make a difference.

 

[avalonandl]

New water may be in your future too. The LS water pumps are prone to failure. Def a flush is needed. Also use s water hose spray on your stack and fins... they get clogged up with time.

 

[PPV12HOE]

Definitely get the system flushed... upgraded radiator and trans coolers will make a big difference... might be able to find a local shop near you to try and flush it before your return trip...

 

[thompsoj22]

ill guess cooling fans not functioning on high, check fan relays in the underhood fuse box. what is the trans temp when your climbing? excessive heat there will overwhelm the radiators ability to maintain the coolant temp at the 210 that your used to seeing. your temps arent normal if your in an XL 6.2. somthing is not right.

 

[Tim907356]

ill guess cooling fans not functioning on high, check fan relays in the underhood fuse box. what is the trans temp when your climbing? excessive heat there will overwhelm the radiators ability to maintain the coolant temp at the 210 that your used to seeing. your temps arent normal if your in an XL 6.2. somthing is not right.

The fans are working....I can hear them running when at a stop after a hard pull. But I’m kicking myself for not checking the transmission temp!...didn’t think about it at the time...

 

[Idriveaho]

New water may be in your future too. The LS water pumps are prone to failure. Def a flush is needed. Also use s water hose spray on your stack and fins... they get clogged up with time.

when I had to change my radiator on my 00 Silverado I decide to spray the old one when I had it out to see how dirty they get. It was so packed full of dirt I was surprised it still did it’s job. I had to replace it though cause it was leaking bad. I’m going to be doing this to the Tahoe before my road trip to the gulf. I don’t have overheating issues but whatever cooling help I can get is good.

 

[Tim907356]

My transmission temperature is reading 220. Seems really really high. My XL only ever got to about 175. Engine is still running hot coming out of the mountains. I’ll try the purge and clean. And maybe change the grill. These perforated units don’t let much air flow.

 

[Doubeleive]

after putting the tru-cool 40k on mine I have to really work it to even seen 165 or a max of 180, normal temps are now around 135-145 (in the summer) or less if i'm just cruising. before it would hit 220 at the drop of a hat.

 

[Tim907356]

Made it home. There no apparent clogging of the fins, but I’m taking the grating off and pressure washing them both in a few hours.
Any recommendations on an aftermarket radiator? The tru-flow transmission cooler is universal, I take it...