Towing and temperature issues

[Fless]

I may have missed it, but was spraying out the radiator and external coolers with water mentioned? Might be something as simple as bugs and dirt in the fins. Or bent fins.

 

[swathdiver]

It appears the trans isn't much to worry about, it never climbs above 220, and already has the heavy duty external cooler, but I may look at replacing all three, radiator, trans cooler and oil cooler, to help ensure longevity. Of course now I need to consider how long the engine may last having had AFM active all it's life. The list of maintenance items just keeps growing, but the wife loves the ride and comfort, and I don't miss all the manual shifting of the previous truck.

Keep the oil clean and you may never have AFM problems. I found out that mine had been completely rebuilt (all new AFM parts) right before I got it, thank the Lord! Maybe yours was too?

 

[lectric74]

I may have missed it, but was spraying out the radiator and external coolers with water mentioned? Might be something as simple as bugs and dirt in the fins. Or bent fins.

That is on the agenda that I mentioned earlier as a simple thing to try to help. I can easily remove the fans and use my pressure washer to push out most. It does have a lot of miles on it, so eventually if I can keep it together I may just replace all the coolers and the radiator.

Keep the oil clean and you may never have AFM problems. I found out that mine had been completely rebuilt (all new AFM parts) right before I got it, thank the Lord! Maybe yours was too?

It's possible, in my haste to buy the thing I didn't check the CarFax like I did with my Lexus. I know it runs strong, but needs the filter screen removed from the oil pressure sensor, but makes no noise. So far it isn't even claiming to need an oil change, and I'll have to look at the mileage on it since purchase to see where I want to change it. It will be full synthetic, and I typically run 4-5k, although most of it's trips are short in town stuff, so I may adjust a bit.

 

[thompsoj22]

It was what really started this conversation. As for me, now that I know approximately what the temp is based on gauge position, I tend to turn the A/C off for a short time once it climbs to ~230, let the temp drop, then turn it back on. Usually the ECT drops quickly once the A/C stops, but fans stay steady. I'm hopeful that a good coolant flush will resolve these higher temps as the truck has 220k, and it may be about due for a water pump and thermostat. It might also benefit from a good flush through the radiator to help clean out all the bugs and debris that builds up and reduces flow.

As for the grill, I'm guessing the Holy Grail grill has the round holes as mine has more of an oval hole in the chrome grill. Either way, my emblem is gone as yours was and I'm honestly thinking the black grill looks better. May give that a shot to see how temps do, but I likely won't tow my trailer again until Sep when I bring it back down from my property. By then temps will below the steady 95-100 that I was towing in last weekend and this weekend. Temps seem to climb when towing steady, even across relatively flat land, at higher speed, while once I drop into town it will quickly drop to the normal range I see when not towing.

I managed to get a pic this weekend, not hooked up but gives a good idea.

View attachment 226833

the emblem was swapped from the oem to the silverado grill, i got the grill off ebay used for $59 free shipping!

 

[97audia4]

Nice! You might just want to replace the radiator with those miles on it. DO NOT get an aftermarket radiator as they do not have the built in restrictors that keep the temperature in check.

Transmission was 160 tonight on the way home, a little hotter than previously, but it was still 90 out and quite humid. Closest photo I took was last June, 92 degrees outside and 156 @ 76 MPH.

It was 99-100 for nearly the whole run south, hot!

Interesting you say dont go aftermarket, I have my mishimoto radiator still on deck to install and was going to replace it before I make a 600 mile trip down to NC with my enclosed trailer in tow.

 

[petethepug]

We’ve gone through two factory radiators on our 08 Denali 6.2L due to cracks in the expansion tanks since ‘14. The first allowed the coolant escape at hot idle with a/c on until the motor tried to overheat. The crack was invisible except where the coolant left traces behind.

I’ve kept an eye on the coolant reservoir since then. The 2nd occurred when I noticed the coolant level dropping and no telltale of a leak. The tech found a crack out of view and replaced it last year. Treat your truck to a new oem radiator just because you tow.

The perfect conditions to waste a radiator can occur and go unnoticed. Roads slurred with asphalt and coated with aggregate or chip sealed condemned an almost new radiator on our VW. The contractor slurred the road and covered it with aggregate that was too fine to embed in the road so it simply kicked up from the tires. A month later the car kept overheating when in traffic or hot days. The fins were almost glued closed from mix of asphalt and sand grit.

Keep your t stat’s poss age in mind too.


Sent from my iPhone using Tapatalk

 

[lectric74]

We’ve gone through two factory radiators on our 08 Denali 6.2L due to cracks in the expansion tanks since ‘14. The first allowed the coolant escape at hot idle with a/c on until the motor tried to overheat. The crack was invisible except where the coolant left traces behind.

I’ve kept an eye on the coolant reservoir since then. The 2nd occurred when I noticed the coolant level dropping and no telltale of a leak. The tech found a crack out of view and replaced it last year. Treat your truck to a new oem radiator just because you tow.

The perfect conditions to waste a radiator can occur and go unnoticed. Roads slurred with asphalt and coated with aggregate or chip sealed condemned an almost new radiator on our VW. The contractor slurred the road and covered it with aggregate that was too fine to embed in the road so it simply kicked up from the tires. A month later the car kept overheating when in traffic or hot days. The fins were almost glued closed from mix of asphalt and sand grit.

Keep your t stat’s poss age in mind too.


Sent from my iPhone using Tapatalk

Coolant level is steady, I've watched it closely since purchase just for cracked tanks which I've experienced on other plastic tank radiators. Thermostat age is unknown, but at least watching and logging using my app, I'm not seeing any signs that it isn't functioning correctly. It opens where it should and doesn't close until below where I'd expect it to close. Warm ups are normal and when the A/C is turned off while towing, the temp drops quickly.

I do think airflow is a part of the problem, so I'm going to fire up the pressure washer this weekend and wash through the radiators and cooler, without the fans to see if it helps. Without the trailer, temps are perfect at about 195-200 all the time. It is really just the increased load causing it, and I'm sure a few minor things can be done to help keep those temps more in check.

 

[swathdiver]

Interesting you say dont go aftermarket, I have my mishimoto radiator still on deck to install and was going to replace it before I make a 600 mile trip down to NC with my enclosed trailer in tow.

Well, those are good radiator from what I hear, some of the guys here have them so I reckon that they have the restrictors to make the cooling system work right. I forgot about that brand when I wrote previously.

 

[Costal_Cat]

Just thought I would post my experiences out there based on my towing.

2012 Denali XL. I got the truck with around 80k on it I think and now have around 135k. I have posted about the temp and towing in several threads but here is a recap of what I have done over time. I like to do one thing at a time and then see how that affects the truck before moving on to the next thing.

I tow a bit mostly in the SE up and down 95 and out 40 to Tennesse and the NC mountains. I have slowly been working on the towing setup. I added bigger and better bump stops in the rear, new shocks and compressor for the rear, converted to passive vs eShocks when I did that. Replaced the trans filter and replaced the fluid. I have flushed it myself by doing the disconnect from the radiator with 3/8th tubing into a 5-gallon bucket while one daughter is filling with new and the other daughter is turning the engine on and off until it was pumping out clean. Flushed the cooling system completely and refilled with dex-cool. That is pretty much the order I approached things and each item improved either ride, handling or temps. The last big trip that ran up the temp was in May over memorial day and the temp in NC & SC got into the 90's. On the 7 hour ride back to the NC coast from our camping trip with the travel trailer the water temp and trans were just too hot IMO. The last thing in my view was to replace the trans cooler with the TruCool 40k. So this past Thursday I did that and immediately saw a huge difference in temp control.

2.5 hour trip up I40 in this crazy heat without towing middle of the day my temp was around 178 - 185, once I hit stop and go it went up to 190's
With the new cooler and no towing in this same heat and route the temp never got about 145 in stop and go and once I was on the interstate and up to speed the temperature dropped to 135 - 142 consistently. Even Friday evening with the heat, I pulled into the driveway and the temp was reading 129 which I have never seen after driving any time of the year.

Now I have not been able to tow a long distance yet but I did grab the boat and the same route from the house to the boat ramp last week the temp was in the 180's, same trip the temp stayed around 148 and only once got up to 153 and as soon as I was moving it was back under 150 in just a few minutes.

So all the things I have done I know have helped incrementally but the TruCool has been the best so far in my view for temp control....

 

[lectric74]

That's interesting, I'll have to consider that, but like you I'm going to do a bit at a time to see the changes. Thank you!