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Discussion Starter #1
I have a 2015 Jeep Grand Cherokee Altitude with a 3.6L engine. I added the trailer hitch myself, so i'm not looking for anyone talking about how it's only rated to tow 3,500 lbs.

My question is, are there any aftermarket engine cooling systems that would help keep the engine from overheating when towing up a steep grade? I have to somehow make this work for towing my small rv. I added a performance chip, and tested it today, and the engine was about to overheat up a 6% grade, so I had to pull over for a bit... Without the chip, there are certain spots where I can barely go 40 mph with the pedal to the metal. My trailer only weighs 4,000 lbs fully loaded - I had it weighed.

So should I put on an aftermarket radiator fan or something? Any suggestions on how to keep the engine cool would be greatly appreciated... I'm trying to make this work without losing my butt on the depreciation of this Jeep and trading it in...
 

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2014 GC Limited 4X4
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Upgrade the radiator with the Mopar setup for towing or look at something from aftermarket like Mishimoto. Another way, but expensive, would be a tuner that can turn the fans on sooner. With 2015 you'll need to unlock the ECM and then run a tuner, which both new would be around the $900-$1000 mark. The plus you would get better performance than the chip you're running.

RockAuto Radiator Choices. Mopar is around $400

Mishimoto claims Increases core volume by 66% over stock radiator Increases coolant capacity by 95% over stock radiator 66% thicker core than stock radiator
 

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Discussion Starter #3
Upgrade the radiator with the Mopar setup for towing or look at something from aftermarket like Mishimoto. Another way, but expensive, would be a tuner that can turn the fans on sooner. With 2015 you'll need to unlock the ECM and then run a tuner, which both new would be around the $900-$1000 mark. The plus you would get better performance than the chip you're running.

RockAuto Radiator Choices. Mopar is around $400

Mishimoto claims Increases core volume by 66% over stock radiator Increases coolant capacity by 95% over stock radiator 66% thicker core than stock radiator
You've given me a lot of good information, and I appreciate it, but please help me break down your answers.

1) When you say "upgrade the radiator with the Mopar setup for towing", does this mean keep the fan I currently have, which is stock, and just replace the radiator?

2) I'm interested in the tuner option. First, how does one go about unlocking the ECM? Does the tuner do that, or the dealer, or ? The tuner option sounds better because there probably wouldn't be labor costs involved, so if i went the tuner route, would I still keep my same stock fan, but program it to come on sooner? Also, do you have a link to a tuner you would recommend?

3) The Mishimoto might be the last resort, and probably the most expensive, so I'll wait on asking too many details about that.

Thanks a bunch!
 

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2014 GC Limited 4X4
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I just looked up the fans as I wasn't sure and it looks like they make two different fans Standard and HD so you would need to swap out both fan and radiator for good measure. I would look into the differences on the fan and if it is plug n play or need something changed in the ECM.

RockAuto fan options standard and HD

There are TWO tuners that I know of Diablosport and HP Tuners.

I have no firsthand experience with HP Tuner. Diablosport can either send in your ECM to get unlocked (Cheapest) or buy an unlocked ECM and tuner I3 or T2 right from them ($400-1000 range). To get the most out of the Diablosport I suggest hitting up Jay Green racing on Facebook for tuning.

Greene Racing

There is a FB page for the 3.6 engine and quite a few recommend HP Tuner with Demigod tuning for the 3.6. So that might be a better option.

Pentastar V6 Performance You can ask further questions on here about HP Tuning.
FB Demigod Tuning

They also make a lower temp thermostat, which I've heard mixed reviews on from Mishimoto.
 
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If it is an auto, I'd be watching transmission fluid temp. Don't think chips and ECMs impact cooling much. you can turn the fans on with a $10 high amp switch switch.
 

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03 WJ, 4.Slow, 3" IRO
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I don't know your specific GC but, have experience with keeping temperatures low while towing. I would recommend against a lower temperature thermostat. A lower temp thermostat can affect the fuel injection and transmission shifting. I would recommend replacing yours with a new, high quality thermostat that has the built-in bypass. This can have the effect of getting the fan to turn on a little sooner.

You did not state how many miles are on your Jeep, but at 5 years old, it could benefit from a cooling system flush and refill. Make sure to use the proper coolant! While I have had great success with products like Engine Ice on other vehicles, they are not chemically compatible with certain antifreeze and can actually damage the motor.

I would recommend the heavy duty fan and shroud. They're designed to move a larger volume of air. A larger radiator is beneficial but in less than summer temperatures, it can take a very long time for the engine to warm up (if at all) and you may need to block a portion of the larger radiator. You can add a simple on-off switch to the fan or an adjustable temperature switch to get it come on when needed.

I would highly recommend adding an external transmission cooler. A lot of the excess heat in the cooling system is generated by the automatic transmission fluid. Excessive ATF temperatures rapidly deteriorates the fluid and can actually damage your transmission very quickly.

One of the most cost-effective methods of keeping the cooling system temperatures in check, is to simply turn the A/C off while climbing hills. The AC consumes power that can otherwise be used for towing and it increases the air temperature through the radiator. Turning the heat on will also reduce temperatures in the cooling system. Do not turn the defroster on, it turns the AC on to help remove moisture from the air. A little momentary discomfort can make all the difference to the drivetrain of your tow vehicle.
 

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Grand Cherokee
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I just looked up the fans as I wasn't sure and it looks like they make two different fans Standard and HD so you would need to swap out both fan and radiator for good measure. I would look into the differences on the fan and if it is plug n play or need something changed in the ECM.

RockAuto fan options standard and HD

There are TWO tuners that I know of Diablosport and HP Tuners.
Take a close look at the electrical connectors for the SD and HD fan. They are not compatible. The SD fan is a two speed fan with the lower speed also having a thermisister in it to control the speed.... ....the HD fan is controlled by PWM in a different wire harness with heavier wires for more current.... ....they has to be more components and can't find anything describing them.....

But I expect you buy an HD fan, you'll find you can't connect it and if you do something to wire up the HD fan to the SD wiring, it won't work right, if not fry something....
 
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