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

[Geotrash]

This was driving around in the city yesterday. This is still like 40 degrees cooler than last year when I had the stock setup.

View attachment 304749

View attachment 304754

Minus the dangling cooler tube, this is my setup. I have the big Mishimoto radiator too. The one difference with my new setup is my engine cooling fans run on hi a LOT more, which I don't mind. I have dual batteries and K5L fans, the voltage stays at 14V all the time. I'm keeping my fingers crossed I won't run in to any hot issues.

Yeah, those are quite typical numbers for the Tru cool. It’s a great cooler. I still have the one I removed to install the Derale, and if my mods in the last few weeks don’t solve my transmission temperature problem on tomorrow‘s trip, the Derale is coming out and the Tru cool is going back in, mounted below the lower grille where the Derale currently is.

 

[Geotrash]

I made a 500 mile trip on Sunday, I have the tru-cool mounted in front of the radiator as pictured above, since my transmission was rebuilt with extra clutches and etc, it seems to run a bit warmer than it used to, at 7-8000ft elevation and 90deg's ambient, ac going and moving at about 75-80mph transmission heated up to 193, that was not the issue, the issue is this made the coolant heat up to 230deg. turning the ac off seemed to help a smidge and coolant temps were then up and down to around 220-225, so I am planning on moving the tru-cool down to the bottom grill and doing like others have and opening up the lower grill holes, just have to figure out some kind of mount. not sure how much air flow it will get at that lower grill or if will effect any other cooling I am thinking probably not because the lower part is below the center of the bumper cover that should be splitting the air 50/50? up/down

I think that will be the golden ticket. For mounting, you could use the same trick I used (borrowed from @thompsoj22) to mount my Derale to the back side of the bumper - just a couple of small door hinges attached to the steel bumper with self drilling screws, and some steel strap to hold it in position from the bottom. If I put the Tru cool back in, that’s the way I’ll go.

 

[Geotrash]

I wonder if the grill opening between the Yukon and Tahoe cause some of this air flow issue. I was above Estes Park the other day with outside temps in the 80's and my trans saw 180 with very aggressive driving up the mountain, and the engine temp never budged off the normal straight up on the gauge. I pay close attention to you guys experiences and am trying to duplicate any hot conditions in case I need to move mine. I go MILES off-road here in Colorado and want to be certain I won't overheat.

I never had any problems with coolant temp with my Tru cool installed until I was towing. Then, even on relatively flat ground the coolant temp would start coming up, but the transmission stayed cool.

 

[Geotrash]

Sweet man. I am looking forward to hearing about your trip. Not much has changed here. I did fill back up with 91 with 10% ethanol and now I don’t see smoke. I had to remind myself that the ethanol was added to help vehicle burn cleaner and since the last tank was non ethanol and I don’t have any cats, then any time I feed fuel to the motor it’s gunna dirty burn and there’s nothing to make it clean. Either way if I have to rebuild it then I have to rebuild it. I also may start the process of getting a duraburb from duramax specialties.

Funny you should mention that. Called Duramax Specialties last week and they’ll do it in 6 weeks for $45K out the door. I‘m still mulling it over.

 

[kbuskill]

Funny you should mention that. Called Duramax Specialties last week and they’ll do it in 6 weeks for $45K out the door. I‘m still mulling it over.

I thought the Duraburb conversion was done on 2500s exclusively?

 

[03_GMC]

Is that using your Denali transferred to a 2500 frame?

 

[swathdiver]

I thought the Duraburb conversion was done on 2500s exclusively?

They do them to 1500s as well, makes them rocket ships with 750 horses!

 

[Geotrash]

I thought the Duraburb conversion was done on 2500s exclusively?

No sir. As 03_GMC alludes to, they take your truck's body and drop it on a low mileage Duramax 2500 truck chassis. They also switch out the front clip with a truck front clip to provide the clearance for the engine under the hood and the space for the radiator, coolers and such, do the paintwork, etc. And then they do all of the integration work with the ECU so it's totally seamless.

 

[Geotrash]

Well all, I think my cooling issues are resolved when towing. We made the same trip over the blue ridge mountains I made a few weeks ago, and the transmission temp topped out at 232º yesterday at the top of the pass. Last time was before I plumbed the radiator's cooler back into the system and it hit 263, so this is a 30º improvement. Coolant temp topped out around 215, all at 80ºF ambient. Rolling on the highway I was steady between 190 and 196 depending on the terrain. Gonna keep the Derale. set up this way it's the perfect solution, in my opinion.

 

[kbuskill]

Well all, I think my cooling issues are resolved when towing. We made the same trip over the blue ridge mountains I made a few weeks ago, and the transmission temp topped out at 232º yesterday at the top of the pass. Last time was before I plumbed the radiator's cooler back into the system and it hit 263, so this is a 30º improvement. Coolant temp topped out around 215, all at 80ºF ambient. Rolling on the highway I was steady between 190 and 196 depending on the terrain. Gonna keep the Derale. set up this way it's the perfect solution, in my opinion.

It would be interesting to know how much of a difference the new baffles on either side of the radiator made.