Grand Cherokee Running Warm Towing

[Nick1994]

Towing a 3200ish pound camper with the 2014 Jeep Grand Cherokee. 3.6L, 147k miles. On the highway the gauge is between 1/2-5/8. In the mountains it got to 3/4. For reference without a trailer it never moves from 1/3. Not sure of the coolant temp exactly as Jeep decided to not make that a digital readout like oil and transmission.

Oil temp got to 239* towing on the freeway, no hills. Not sure what it was in the mountains as I wasn’t driving it. Transmission seems fine at 204*.

Once I got off the freeway and let it idle the temp went right back down to normal. Which is all the exact opposite of the running warm issues I have with my old ‘96 Jeep.

Nothing blocking the radiator/condenser. It got new radiator hoses and thermostat(s) (I guess it has 2?) and a new OEM radiator in 2018 at about 104k miles. I’ve never had to add coolant, it’s always full in both the radiator and overflow. Electric fan blowing nice and strong.

First 2 pics are of towing flat on the freeway, 3rd pic is after I got home right off the freeway and let it idle for 15 min, the temp gauge went right back to where it has been for years. It’s never really moved from there.

I’ll try to take it out towing with my OBD reader maybe next weekend and get exact coolant temps. Main concern is pulling in the mountains and having a bigger issue.

 

[tnt_motorsports]

can you run in a lower gear and keep the torque converter locked up. This avoids extra heat in the engine and transmission because it is more efficient. Also the higher RPM's will keep the coolant flowing.
Does the front of the radiator need cleaned (bugs & road grime) ?

Just my $0.02

 

[ekrampitzjr]

Has anyone EVER used an aftermarket leak sealer in the cooling system?

 

[racer12306]

In my experience, these engines (at least in our Pacifica) run a little on the hotter side when not towing.

 

[oldhp]

It's 102° and your pulling a 3200lb'ish trailer. Oil temp goes down when you stop. I don't think you have a problem.
All stock? Bigger tires? Electric or mechanical fans?
My stock 2022 RAM 1500 Classic runs 218°-220° oil temp when running 75mph on the interstate not towing anything.

 

[Davejam]

At least the new models have a tow prep package which includes "heavy duty engine cooling".
Not sure exactly what that refers to, larger radiator? pump? Reservoir?
But was that the case in 2014 and does yours have it?

 

[Nick1994]

can you run in a lower gear and keep the torque converter locked up. This avoids extra heat in the engine and transmission because it is more efficient. Also the higher RPM's will keep the coolant flowing.
Does the front of the radiator need cleaned (bugs & road grime) ?

Just my $0.02

It runs already in 5th at 3,500 RPMs, I tried making it up shift to 6th and it didn’t change the temperature either way.

Has anyone EVER used an aftermarket leak sealer in the cooling system?

Never

It's 102° and your pulling a 3200lb'ish trailer. Oil temp goes down when you stop. I don't think you have a problem.
All stock? Bigger tires? Electric or mechanical fans?
My stock 2022 RAM 1500 Classic runs 218°-220° oil temp when running 75mph on the interstate not towing anything.

Tires are 1 size bigger, but not super big.

I’ve towed this weight before from Oregon (in the winter) and it handled it much much better than this camper. I think it’s the wind resistance, like pulling a parachute.

At least the new models have a tow prep package which includes "heavy duty engine cooling".
Not sure exactly what that refers to, larger radiator? pump? Reservoir?
But was that the case in 2014 and does yours have it?

It has a factory trailer hitch, not sure what it all entails. There is a HD electric fan online, but I guess those have different electrical connectors and PCM programming.

 

[Marcozi]

Has anyone EVER used an aftermarket leak sealer in the cooling system?

NEVER!

 

[AdmiralYoda]

Seems about right. You are towing in worst case conditions. Mountains and very hot temps. And you are pulling more than 3200lbs., you have to add the weight of the passengers and cargo as well.

I wouldn't worry too much about those temperatures but I'd want to make sure I have a very good synthetic oil and maybe change it more often. Those conditions sum up "Severe Use" on the maintenance intervals.

Might not be a bad idea to add an external transmission cooler if it doesn't have one...or a larger one if it does. Might not be a bad idea to look into an engine oil cooler with a thermostatic bypass as well.

 

[Rand]

Sounds normal IMO.
you have a real gauge.. still in the normal range... one of the reasons why they went to "dummy gauges" is so people
wouldnt think something was wrong when it wasnt.

Also it might run cooler at a HIGHER rpm vs lower. so it would be 4th vs 5th..

Those campers are a big load as you mentioned the drag(air resistance) is immense.. .. add in 100F temps.. and yes it will run hotter.

For example my 650lb utility trailer will drop my mpg from 28 to 15 if the gate is up and its not a solid gate.. (slots/holes in it)

A camper is worse.

or to think of it another way
the load requires a major increase in HP.. producing HP= producing more heat.

so if you went from needing 15-20hp to cruise along.. now you need 60hp for long periods. producing 3x the heat.

 

[wwillson]

I find in my Durango, the two largest factors in engine oil temperature are ambient temperature and engine RPMs.
Examples:
75 MPH air temp 75°F - engine oil temp 194°F
85 MPH air temp 75°F - engine oil temp 199°F

75 MPH air temp 95°F - engine oil temp 205°F
85 MPH air temp 95°F - engine oil temp 212°F

Add 3200lbs AND the air resistance of the trailer, I don't think the engine oil temp is out of line. However, my water temp virtually never varies where the needle points. I run a nylon window screen in front of my radiators to catch all the bugs and cotton wood fluff. You can't believe how much debris it keeps out of the radiator. I will put money on your condenser and radiator airflow being restricted.

The highest oil temp I've ever seen in the Durango was about 225F descending from the Eisenhower tunnel in Colorado using the engine as a brake. The RPMs were about 4000 for a few minutes, although there was no combustion heat, there was a LOT of friction. Amazing that friction alone can reject that much heat.

This is what my screen looks like after about 10,000 miles and 6,500 miles of that is in the last month. I am likely going to need to put a new screen in soon.

Wrap your radiators!

 

[2strokeNorthstar]

In high Temps going up a grade, temp will climb even on a brand new vehicle. I rented a new Chevy something full size car and was 115 in Arizona, not towing, going up a grade it got to 3/4 on the gauge. Probably just comes down to how accurate they want the gauge to read.

 

[Nick1994]

I find in my Durango, the two largest factors in engine oil temperature are ambient temperature and engine RPMs.
Examples:
75 MPH air temp 75°F - engine oil temp 194°F
85 MPH air temp 75°F - engine oil temp 199°F

75 MPH air temp 95°F - engine oil temp 205°F
85 MPH air temp 95°F - engine oil temp 212°F

Add 3200lbs AND the air resistance of the trailer, I don't think the engine oil temp is out of line. However, my water temp virtually never varies where the needle points. I run a nylon window screen in front of my radiators to catch all the bugs and cotton wood fluff. You can't believe how much debris it keeps out of the radiator. I will put money on your condenser and radiator airflow being restricted.

The highest temp I've ever seen in the Durango was about 225F descending from the Eisenhower tunnel in Colorado using the engine as a brake. The RPMs were about 4000 for a few minutes, although there was no combustion heat, there was a LOT of friction. Amazing that friction alone can reject that much heat.

This is what my screen looks like after about 10,000 miles and 6,500 miles of that is in the last month. I am likely going to need to put a new screen in soon.

View attachment 163443
View attachment 163444

Wow, this condenser looks nothing like that. I'm sure it's dirty though. It's just so hard to get in there. I think I'll be taking the bumper off so I can hose it out good. The grille opening is too small.

 

[wwillson]

Wow, this condenser looks nothing like that. I'm sure it's dirty though. It's just so hard to get in there. I think I'll be taking the bumper off so I can hose it out good. The grille opening is too small.

The Durango has a very open radiator and all you need to do is take the top cover off the radiator/condenser, but it's not simple. It will take about an hour to get the top off, put the screen in (simple), and put the top cover back on.

 

[meep]

Sounds about right. I assume the camper is a solid camper and not a pop up. The frontal area on those presents a real load.

oil temp actually seems pretty good for an engine being worked, especially that hard. Oil contacting the undersides of the pistons will probably be 450F considering the load.

are you trying to hold the posted speed limits on the climbs? Get out of that mindset if you are, it’s not neccessary.

agree with above also, stay out of overdrive gears, even on the flats. You want it spinning and you want the TC in full lockup, not unlocked, not partial-modulated. You want the engine in its power band, all fluids moving, and small driven gears (OD) out of the loop. Even v8 trucks will send to 4500 rpm or more if you’re trying to pull a camper up a mountain pass. I’m not sure of the torque curve of the 3.6, but my guess is that it needs 3500-4000rpm when it wants to dig in. It shouldnt hurt it at all.

also, do note that your engine and transmission are actively liquid cooled. Your rear diff is not. I learned that the hard way in a tundra which used cartridge bearings - got the axle so hot the grease seaped out the front and rear and destroyed the bearings. Was pulling a 6000lb camper, truck was rated for 6900. Engine stayed normal temps and transmission hit 230 iirc at its peak.

different engine, but my grand Cherokee with the 3.7 worked hard pulling box trailers on steep grades. The WA580 was … probably my favorite transmission to date - and handled ALL of the load like, “yep, been here before. you?” The 3.7 would get hot enough to start demonstrating something between pin slap and rod knock, if using spec oil. I learned when towing with it, go up a solid grade of oil for the engine.

I also went to a slightly thicker gear oil in the back, but the WK was also known for axle tube alignment issues the years I had mine. keep an eye on axle temps, suggest an IR temp gun, $40 at Home Depot.

 

[Marcozi]

The Durango has a very open radiator and all you need to do is take the top cover off the radiator/condenser, but it's not simple. It will take about an hour to get the top off, put the screen in (simple), and put the top cover back on.

I'd do it because that pic sure shows a lot of debris in front of the condenser/radiator.

 

[wlk]

Keep it out of O/D, see if you have an external oil/trans cooler- if not add one to at least the transmission cooler and just slow down. See what 55mph does to it as you have a big sail attached to you. We tow our 5000-6000 k camper at 60mph max in the flats and 40-45 going up hills/mountains~3000-3500rpms. Also keep the cruise control off when going up hills so it can slow to an even speed. You are putting too much on your eng/trans. My temp gauge stays the same towing, as you just need to take it easy.

 

[RooflessVW]

If the "middle" of the gauge is normal, then to my eye it looks like it's only running slightly warmer than usual while towing and running too cool the rest of the time.

So an open thermostat.

 

[Nick1994]

If the "middle" of the gauge is normal, then to my eye it looks like it's only running slightly warmer than usual while towing and running too cool the rest of the time.

So an open thermostat.

The last pic has been the norm before and after it's had a new thermostat, it also has insanely fast heat in the winter. I'll try to get some OBD2 readings this weekend.

 

[dogememe]

I wouldn’t worry about that, nothing wrong with it. Of course the temp is going to go up a little when you’re towing a trailer on a hot day.