Overheating - Can I use coolant additive to keep temps down?

[Jeeperz Kreeperz]

I’m on an extended 7,000-mile camping trip in the 4xe. I’ve overloaded the Jeep at about 1,300 pounds of cargo and people. I installed Air Lift 1000 coil spring airbags, which completely resolved suspension and handling issues. First 2,500 miles were uneventful. But in attempting to get over an 8,000 foot pass, she got up to 230 degrees. It didn’t set off an overheat light, but I had to pull off a couple times to let her cool down.

I judiciously switched between electric and ICE, which does delay the overheating. Switching to electric would stop the temps from climbing (but not reduce them). Then, after about a minute, I would switch back to ICE, which would drop temps by 10 to 12 degrees F. Then they would climb up again. Rinse, lather, repeat. This burns through the EV battery charge very quickly.

We have more (and larger) mountain passes on the itinerary.

Question: Can I add a coolant additive?

I can drop about 150 pounds (well, not ME!). But looking for other ways to keep from overheating.

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[johnnyj]

I would stay away from coolant additives. They do way more harm than good. Temps in the 215-220 range are not unheard of in JLs when going over passes. Your vehicle is equipped with lights which will warn you if your temperatures exceed specs. Honestly, that might be normal for operating a 4xE under heavy load. To reduce heat, you're going to need to reduce load, which means reducing weight. If this is one of those "overland" builds that might be, if you examine it honestly, carrying a bunch of stuff you don't actually need, I would look honestly about giving your Jeep a diet. Remember, the 4xE is already 1k lbs heavier than a normal 2.0t JLUR due to all that extra hardware.

 

[jellis4148]

Problem is you have overloaded your Jeep. The Payload is around 1,100 pounds. Airbags don't give you more payload. You are over working the Jeep. Adding additives is a bad idea. I would either get rid of some weight, or take it easy with it. Not trying to be a smart ass, but those numbers are for a reason. If you are overloaded you are also putting yourself and others in danger.

 

[1quick1]

Why do you think it's overheating?

 

[GreenJK]

I used this product with some success when I lived in Arizona and my overweight trailer-pulling JK would get hot going over the mountain passes, but ultimately, an aftermarket 3 row core radiator finally solved the problem for good. https://www.redlineoil.com/waterwetter

 

[Left Field]

Why do you think it's overheating?

^^^^^

I don't think you are overheating either. Someone may be able to weigh in with the temperature for the overheat light.

Yes, you have some extra weight, that's its own issue, but its peanuts compared to if you were towing.

Regarding the 230F coolant temperatures, I tow extensively, including mostly in the west but have also gone coast to coast. Two weeks ago we completed a 3000 mile trip in MT, ID and WY with temperatures often well into the 90's and occasionally over 100F. Many long, steep passes to climb in those temperatures. I don't give coolant temperature a second thought unless it gets over 235F (which is when my fan fully engages and brings full cooling capability to bear).

Note that the JL has a 21psi coolant pressure cap, which raises the boiling point to around 280F, not that you want to go there, but the vehicle is designed to have a robust margin against boil-over. Boil-over / loss of coolant is what damages an engine.

One thing that has given me heating trouble occasionally is restricted radiator air flow - in my case bug build-up on the radiator, which did occur on my last trip. A winch, lighting or other grill obstructions could do the same.

In the rare event of excessive coolant temperature, three items in my bag of tricks:
1) Slow down & shift down (reduces load on the engine, which means less heat generated)
2) Turn off the AC during the climb (reduces the heat load on the cooling system)
3) Roll down the windows and turn the heater on max heat (removes heat from cooling system)

Someone else can weight in on the coolant additive question; skeptic.

 

[Echo4papa]

In the rare event of excessive coolant temperature, three items in my bag of tricks:
1) Slow down & shift down (reduces load on the engine, which means less heat generated)
2) Turn off the AC during the climb (reduces the heat load on the cooling system)
3) Roll down the windows and turn the heater on max heat (removes heat from cooling system)

Someone else can weight in on the coolant additive question; skeptic.

I think the AC and Heat run off the main battery in the 4xe so I'm not sure this will have the same sort of impact.

 

[GreenJK]

Turning off AC and rolling down the windows while running the heater full blast was my go-to trick to get over the highest passes. It does work if you can stand it. Also slowing down as Left Field mentioned also helps take the load off engine.

 

[michail]

Does the 4xe have a heater core? I thought it was all HVB.

 

[JimLee]

Not a 4XE but I've had my 3.6 up to 256 without overheating. These new aluminum engines and new coolant formulas can run a lot hotter than what people are used to.

 

[Left Field]

There are two heaters. An electric one that appears to be quite small and a internal combustion one that is 2.0 liters and makes tons of heat as a by product of operation.

(Thanks Greg @ SnB4xe)

It appears that the heater operates using the best available source, which would be the engine while it is running.

 

[LongTimeListener]

JKs regularly got up to 230 when working hard and it never, AFAIK, affected the long-term health of the Pentastar. Jeep seems to have improved cooling on the JL/T and they do run cooler. However, I wouldn't worry about 230-235 unless it keeps climbing from there.

 

[Black96z]

When we were towing our popup the temp would rise a bit. I don't remember the number, but the lights never came on. I found that if the traction battery was not dead, I could put it into manual most to make it run as a true hybrid and the EV power would reduce the load on the engine by about 33% (Looking at the EV Page). The Jeep would rapidly cool down at freeway speeds and then I could click it back to auto again.

Just because you have a little more weight in the Jeep than recommended, you shouldn't be near the maximum capacity of the drivetrain... Its rated to tow 3500lbs.

 

[GATORB8]

If you can hold speed at grade with just the electric motor, it's hard to believe the 2.0T is overworking at the same power requirement.

You do have several stacked radiators, including the turbo water to air intercooler which may be running hot since the turbo is able to compress the air an additional 4 psi to hit the same intake pressure at that elevation.

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