High engine temps towing with Jeep diesel - a problem?

[jackconn]

We're 3 weeks into a 3-month trek from Raleigh through the south, Texas and points west and north. I've got a 2014 Jeep Grand Cherokee with the 3L diesel and a 7400 lb towing capacity. We're towing a 21' Rockwood Mini Lite 2104S with a total weight of under 5500 lbs.

I've noticed the engine temp gauge (water temp) will occasionally creep up to within a half-marking of the red zone but has never gone into the red. I've attached a photo of the gauge. The needle hangs at various spots but has stayed at the shorter line that's adjacent to the red zone at times.

This is well above the normal operating temp but I know it's under tough conditions. I've seen this with air temps of 75F but of course was most concerned when driving uphill in 100F, most recently in Big Bend NP. Transmission and oil temps were both high but not as close to the red zone on their gauges.

Of course, slower is better and hills are tough. My max speed is 55-60 when I'm seeing the temp climb (60-65 any time), much slower of course when going up steep hills. The temp will drop when going back downhill.

The engineer in me says this is what the cooling system is supposed to do - it's working really, really hard and is keeping temps below the limit under almost-worst-case design conditions.

The pessimist in me (and my wife) says I'm about to blow a hose or something which will happen in the middle of nowhere with no safe place to pull over and no cell service. And/or I'll fry the engine and have a bigger problem.

Opinions?? Thanks.

[SilverArrowPro]

Possible that your tstat is failing. Had this intermittent with my Cummins before total failure.

[Champ203]

There is a valve that fails on those cooling systems. Are you keeping an eye on your coolant level? Not the t-stat.

Peace,
Don

[jackconn]

Thanks for the quick replies...keep 'em coming!
Thought about the tstat - and will probably have someone replace it when in for oil change in about 1500 miles; sooner if it seems to get worse. That's a good guess since it seems to dwell at various levels at different times. But I think once to temp the tstat would be open and stay open, true? Unless it's failing in a way that makes it dither around the fully-open position. (Which seems like pretty odd behavior if true.)

I hadn't heard about a valve in the cooling system that could fail. Yes, the level was a shade below the Min line so I filled it to Max a couple days ago. Just re-checked and it's still well above the Min line.

[325BH]

Originally Posted by jackconn

We're 3 weeks into a 3-month trek from Raleigh through the south, Texas and points west and north. I've got a 2014 Jeep Grand Cherokee with the 3L diesel and a 7400 lb towing capacity. We're towing a 21' Rockwood Mini Lite 2104S with a total weight of under 5500 lbs.



I've noticed the engine temp gauge (water temp) will occasionally creep up to within a half-marking of the red zone but has never gone into the red. I've attached a photo of the gauge. The needle hangs at various spots but has stayed at the shorter line that's adjacent to the red zone at times.



This is well above the normal operating temp but I know it's under tough conditions. I've seen this with air temps of 75F but of course was most concerned when driving uphill in 100F, most recently in Big Bend NP. Transmission and oil temps were both high but not as close to the red zone on their gauges.



Of course, slower is better and hills are tough. My max speed is 55-60 when I'm seeing the temp climb (60-65 any time), much slower of course when going up steep hills. The temp will drop when going back downhill.



The engineer in me says this is what the cooling system is supposed to do - it's working really, really hard and is keeping temps below the limit under almost-worst-case design conditions.



The pessimist in me (and my wife) says I'm about to blow a hose or something which will happen in the middle of nowhere with no safe place to pull over and no cell service. And/or I'll fry the engine and have a bigger problem.



Opinions?? Thanks.

I've never seen water temp gauges get close to hot, even under hard working loads, if the system is functioning correctly (no mechanical issues, proper coolant, radiator not plugged, etc.).

I would suspect something is amiss. A poster suggested low coolant which is a good idea.

I wouldn't think a 5,500 lbs trailer is working the diesel too hard.

[SilverArrowPro]

I believe my tstat rubber was actually plugging the valve, when it finally failed, was mid Winter and ended up with no heat. Another issue I've seen is too rich of an antifreeze solution, may want to get a tester.

[FirstTracks]

I have absolutely zero experience with your vehicle. But for the sake of comparison I'll give you our experience thus far with our new TT, which has much closer tolerances.

I drive a 2007 Toyota Tacoma 4.0L V6 with a manual transmission. It has a 6,500-lb. towing capacity. In March we bought a 2016 Evo 2050T, which weighs 5,500 lb. dry. I'm therefore pretty much at my limits for both towing capacity and tongue weight when wet. And I live in Utah, which has some rather large hills to tow across. Yeah, we bought too much trailer, but compared to everything we saw over the previous 9 months the 2050T was a no-brainer -- it had to be ours.

In our first few outings I've been deliberately pushing the Tacoma, because I'm indecisive on whether or not it's enough truck. I can keep it at 70-75 mph on flat ground in 5th gear, although much of that time the pedal is to the floor or nearly so. On grades, including some that rise 3,000 vertical feet in 6 or 7 miles, I'm dipping as low as 45 mph, although 55 mph is more typical (I told you I was pushing it hard). Despite this, I've never seen my temperature gauge depart in any way from where it sits normally.

So, IMO something in your situation is clearly amiss mechanically.

As an aside, I've test driven full-size Toyota, Ford and Dodge trucks this week, but to be honest (and no offense to you full-size truck owners out there) I really don't like any of them.They feel huge while driving. I love my Taco, which at 108k is just entering mid-life, and I also off-road camp in the mountains and desert (without the TT, of course), so it bothers me that none of these trucks I'm seeing are as off-road capable. Frankly they're too wide to fit on many of the trails around here, too. I'm getting nearly 11 mpg while towing, which ain't bad considering I get 16-17 highway MPG when not towing. Finally, the Taco is paid for and I really don't feel like starting another truck payment right now. So I think that I'll probably continue to be that slow guy on hills in the right lane.

[Jmkjr72]

Originally Posted by jackconn

I hadn't heard about a valve in the cooling system that could fail. Yes, the level was a shade below the Min line so I filled it to Max a couple days ago. Just re-checked and it's still well above the Min line.

If you filled it to max a few days ago it should still be at the same level. If it's not this tells me something is amiss a bad t stat is possible I wouldn't wit 1500 miles till the oil change till adress this issue

A proper working cooling system maintains a steady temp once you reach operating temp it's normal to see maybe a few deg higher but nit sweeping it to just below the danger zone

[jackconn]

Great input...yep, I'll get the tstat changed next opportunity and hopefully that will solve the problem. Thanks, all!!

[up2speed4]

Towed a Flagstaff Mini Lite (3300 pounds dry) with 2005 Jeep Grand Cherokee, 4.7 V8 with 79,000 miles over Siskiyou in Oregon while in temperatures between 100 and 110 degrees. Temperature gauge did the same. Rose up to almost red line but it held. My scheduled maintenance was always performed by the local Jeep dealership on time. If you have taken good care of your Jeep, I wouldn't worry about it.

[Rick_Geneseo]

These are all good suggestions. Don't forget to check the radiator cap.

[510Rick]

You need to get on a Jeep diesel forum and see what those folks are seeing with there Jeeps . Could be nature of the beast could be a lazy Tstat or even an electric fan not coming on .

[TandSH]

Originally Posted by Rick_Geneseo

These are all good suggestions. Don't forget to check the radiator cap.

+1

If you are losing coolant you either have a serious engine condition, an external plumbing leak or a failed radiator cap. Look around the engine and engine bay for signs of a leak including hoses to/from and around the heater, etc. If all is dry, change radiator cap. A faulty t-stat will not result in loss of coolant but a faulty radiator cap will not keep proper pressure, slowly lose coolant out of the overflow tube and result in insufficient cooling capability when the engine is loaded as in towing. More critical for a diesel than a gasser. It's also the cheapest thing to address, so stop in the nearest town with a dealer or good auto parts store and buy and install a new cap before you spend time/money on more invasive repairs. Don't even get the old cap tested, just replace it and give us a follow up post.

[johnbrew]

Might consider your fan clutch. If it leaked any of the viscous oil out it will not engage fully. Had the same symptoms as you call out. Had this happen on my Tundra with only 10k on it. Easy fix. That is if it does not have electric fans ( not familiar with the Jeep)

[SidecarFlip]

My opinion is that analog gauges in any mass produced vehicle are just a hair more accurate than an idiot light.

Go get yourself an accurate Stewart Warner analog gauge and sending unit and then see if it's really above normal or if the gauge is wacky.

[tx333]

Originally Posted by SidecarFlip

My opinion is that analog gauges in any mass produced vehicle are just a hair more accurate than an idiot light.

Go get yourself an accurate Stewart Warner analog gauge and sending unit and then see if it's really above normal or if the gauge is wacky.

Agree, verify the actual temperature first and go from there.

Story from previous experience I had with a similar issue on a Ford E350 chassis motor home with a 460 gas. It ran near to hot all the time. Previous owner said dealer told him it was normal. Some years back I worked as agricultural and and industrial equipment mechanic and service manager so I did verify it was running near hot and proceeded to fix it. Changed out thermostat, water pump, larger capacity radiator, new clutch fan, flushed system and it still ran near hot. Basically I was at a loss at what to do. Got some suggestions from a drag racing team. Went to Jegs got a Mr Gasket hi-performance thermostat and a bottle of water wetter. The 460 ran a little on the cool side of normal from that point on. The normal thermostats had a smaller opening in them restricting water flow. The MR Gasket thermostat had a noticeably larger opening allowing enough flow to take advantage of the larger radiator. Water wetter probably helped some too but there's no doubt the thermostat was the fix.
For your Jeep there could be many different issues as already suggested. I would think with a diesel it was intended to tow some. Let us know what you figure out.

[jfshagar]

I had the same prob on my 05 liberty 2.8 MB diesel. Had the computer tweeked by Green Diesel Engineering and low and behold no more problem.

[mnoland30]

Mine does the same when towing. I read up on it, and talked to another owner who said Jeep programmed the computer wrong. My friend said he checked his engine temp with a remote thermometer (also handy for wheel bearings and tires), and it was running fine. He said the dealer reprogrammed it to read correctly. We have 2005 models, so I would hope they have fixed that problem, but who knows? Amsoil claims their water wetter will lower temperatures about 15 degrees. I'm going to try that in my 6.0 diesel this summer.

[CedarCreekWoody]

It could be that your thermostat is not opening fully. That could allow enough coolant to pass for normal conditions but not an adequate flow when under a heavy load.

[rebeltown]

Transmission temp may be high also. If your coolant temp is high then your transmission temp is also up there since your primary xmission cooler is in your radiator. Check your xmission fluid to make sure it is at the proper level and not showing signs of overheating. Need to change fluid more frequently since you are pulling a trailer also. Good luck.