3.0 vs 3.6 MPG towing

[AZ-Chris]

On my road trip to from Phoenix to Salt Lake City, I closely monitored the gauges shown on the off-road page of the UConnect screen. It was only on the 6-7% mountain grades where I saw oil temperatures reach what I saw as a maximum of 251 degrees (ambient was 97 degrees). This was NOT towing, but maintaining speeds of 70 mph. I only saw these maximum temperatures for a short duration, probably less than 2 or 3 minutes and only near the crest of the hills. Temperatures would drop to the 230s within a minute of cresting the hill. If I dropped my speed by 5 mph, the temperatures didn't seem to build as high. I'm sure engine temperatures will go higher if it were under a towing load, but I think if you were to keep the speeds down to a reasonable 65 mph and maybe try to avoid the hills on really hot days (impossible for Arizona summers) you'd be OK, provided you keep an eye on the temperatures.

I started taking photos of the UConnect screen on the return trip and ambient temperatures were lower and I was driving a bit slower, but here are two hill crests . . . notice altitude and ambient temperatures.

My trip to Salt Lake City was specifically to look at an trailer I hope to acquire within the year. I'm now investigating the feasibility of adding an auxiliary oil cooler to the engine.

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[Wrangler man]

On my road trip to from Phoenix to Salt Lake City, I closely monitored the gauges shown on the off-road page of the UConnect screen. It was only on the 6-7% mountain grades where I saw oil temperatures reach what I saw as a maximum of 251 degrees (ambient was 97 degrees). This was NOT towing, but maintaining speeds of 70 mph. I only saw these maximum temperatures for a short duration, probably less than 2 or 3 minutes and only near the crest of the hills. Temperatures would drop to the 230s within a minute of cresting the hill. If I dropped my speed by 5 mph, the temperatures didn't seem to build as high. I'm sure engine temperatures will go higher if it were under a towing load, but I think if you were to keep the speeds down to a reasonable 65 mph and maybe try to avoid the hills on really hot days (impossible for Arizona summers) you'd be OK, provided you keep an eye on the temperatures.

I started taking photos of the UConnect screen on the return trip and ambient temperatures were lower and I was driving a bit slower, but here are two hill crests . . . notice altitude and ambient temperatures.

My trip to Salt Lake City was specifically to look at an trailer I hope to acquire within the year. I'm now investigating the feasibility of adding an auxiliary oil cooler to the engine.

Those numbers are more of a real world scenario for my 3.0 Read a few posts, guys are towing a trailer and claiming numbers much lower, I'm not sure how they're achieving that but it might be the ambient temperature. Most of my Highway is similar climate, Desert California Heat. The Honey Cone insert on the front grill has small openings on my 2020. All the 2021 3.0s I've seen so far, are the same as Gladiator they all have larger holes. Would like to remove my grill inserts
and see if I get a difference in the gage temperatures. Don't think it will make I noticeable difference but I'm willing to try. When I tip over the 250 on the oil temp is when I start to get concerned. Seeing the water temps at 230+ at times, is also concerning. After all water boils at 212.

 

[AZ-Chris]

The TFL Truck guys are relaying the information they received from Ford Engineering that towing weight rate ratings need to be reduced by 2% for every 1,000 ft. in elevation gain. so if you're at 5K ft elevation, you should reduce your trailer weight by 10% (from 3,500 lb max to 3,150 lbs). I'm regularly above 5K ft in elevation, often in temperatures near or exceeding 100 degrees. Southern California isn't any better.

 

[grimmjeeper]

Those numbers are more of a real world scenario for my 3.0 Read a few posts, guys are towing a trailer and claiming numbers much lower, I'm not sure how they're achieving that but it might be the ambient temperature. Most of my Highway is similar climate, Desert California Heat. The Honey Cone insert on the front grill has small openings on my 2020. All the 2021 3.0s I've seen so far, are the same as Gladiator they all have larger holes. Would like to remove my grill inserts
and see if I get a difference in the gage temperatures. Don't think it will make I noticeable difference but I'm willing to try. When I tip over the 250 on the oil temp is when I start to get concerned. Seeing the water temps at 230+ at times, is also concerning. After all water boils at 212.

My 2021 has the gladiator style honeycomb.

 

[theMANIMAL]

If you drive the 3.0ED like a 3.6 gasser your fuel mileage will be reduced.
I learned this 20 years ago with a Duramax vs the gasser equals in the HD.
A diesel must be driving like a diesel to achieve greater MPG. This is why I bought a JLURD.

Would you mind expanding on this a bit? This is my first diesel vehicle, however not my first turbo vehicle (nor first time driving a turbo diesel, if that matters).

 

[NCJL]

Would you mind expanding on this a bit? This is my first diesel vehicle, however not my first turbo vehicle (nor first time driving a turbo diesel, if that matters).

My experience with Diesel over the last 20 plus years to get better fuel mileage.
Only use #2 diesel. The Bio stuff reduces MPG. I think it also makes the engine run hotter.
When accelerating don’t go over 2K RPM.
When cruising keep the RPM between 1400 and 1700 RPM. This is easy with an 8 speed, with 2 overdrive gears.
Use the torque to slow down using the brakes less.
Rabbit starts kill MPG on a diesel.
Be patient when recovering from a slow down due to traffic or grade.
Diesel really shines while coasting (still in drive). Its like free MPG when coasting. Do this by not using the brakes for longer coasting times and when going down a grade.

All of the above would also apply to a gasser. However it would be a slug. No fun to drive.
A diesel can be driving like described above and still be enjoyable.

I worked far a company that switched from gas to diesel trucks in the early 2000’s. We all drove the same trucks. The MPG difference between drivers was slight with the gasser and much more with the Diesel. All the diesel trucks averaged 3 to 5 MPG more than the gas equivalent. Some guys were getting almost 10 mpg more. I was not one of them. I talked to one that was averaging over 20 mpg. That’s when I was told you gotta drive a diesel like a diesel.

Another example. We used to do a yearly trip from LA to Moab every year. About 12 hours drive time. We did this with family and friends. I would always lead and be first to get to the campground. My dad would always be the last arriving at camp approximately 5 minutes late than me. He drove a MB Sprinter with an RV conversion while pulling a Samurai on a trailer. We all drove different types of vehicles pulling various set ups.
My dad averaged 22mpg on these trips. No one was close to those numbers. We all joked about him driving like grandpa. In reality he was driving smart. Smarter than anyone else in the group. He showed up to camp 5 minutes later me (1st) and saved countless gallons of fuel over a 12 hour drive.

Buy a diesel for MPG with torque, towing, and heavy builds.

Do not buy a Diesel for quickness, launch times, 0 to 60 times and so on.

 

[theMANIMAL]

<snip>

Thanks for taking the time to write a detailed reply - much appreciated!

If you were to shift the RPMs a little higher, it sounds like how I drive my 6 speed turbo 4 cylinder hatchback when I commute to work. I get ~3 mpg better than my buddy with the same car. I think this will be wasy to replicate in the EcoDiesel.

It is interesting to note this driving style vs others that say to work the EcoDiesel hard and have a lead foot.

 

[NCJL]

“It is interesting to note this driving style vs others that say to work the EcoDiesel hard and have a lead foot.”

I do work the ED. I pull a 4000lbs trailer at least once a month.

I’m not a Diesel mechanic. People say these new motors aren’t million mile motors anymore, even half that. When diesels were million mile motors they redlined at about 2K RPM. The new modern diesel is double that. I think this is done to give the vehicle a more gasser type feel. Open the acceptance of the diesel to more paying customers. Higher RPM means more wear and less MPG. It’s a balance thing. Im just happy we have the choice.

All the EPA stuff is a different story. I can see all the reasoning for all the different view points.
I’ve owned many Duramax’s, VW TDI’s, one MB, and currently a ED. I’ve never had an issue with the EPA stuff on any of the Diesels I’ve owned or driven. I can see the more modern set ups becoming a problem for reliability. Deal with that when/if it happens.

 

[GearWhore]

We bought our JLURD specifically for the overland range and for towing our boats and camper. Built on beadlocked 37s our typical mileage is 22-24 including city, mountains, passes, and off-road on almost every tank. I've seen a couple tanks around 25-26 mpg on slower (~60-65 mph) pavement trips. Towing the ~3800 lb boat I now see 17-18 mpg and towing the ~2800 lb camper I see around 20 mpg (these trips always see quite a bit of dirt mountain trials, 4lo, and idling).

Same trips with the 2014 JKUR manual (I know, not quite direct comparison) on 34s would return around 13 mpg towing the ~3800 lb boat. I've also had the 3.6 in my 2011 WK2, then the 3.0 in my 2018 WK2. With the WK2 I noticed more difference in mileage between towing or not with the 3.0 (gearing?). That torque though...

As far as different driving with the diesel, I think the style I find works best is most similar to other turbo cars. Typically rolling onto the throttle a little more slowly and allowing the turbo to build pressure is faster and more efficient than just mashing the skinny. I am amazed it can still jump off the line but for the most part I do try to keep the throttle movements slow and minimal and watch the road way ahead to plan for momentum conservation (traffic curves, hills, all of that).

 

[NCJL]

After all water boils at 212.

Yes. However we have a mix with coolant/antifreeze, plus water. The boiling point is raised 10 to 15 degrees and with the cooling system operating under pressure the boiling point is even higher.

286 degrees is the boiling point with a 21psi radiator cap.

Temps in the 230 degree range is normal for a modern engine.

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