Legitimate question to diesel owners....

Tpflyer

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I wouldn't dissuade anyone from getting a diesel JL. I am in the process of trading in my Diesel Grand Cherokee for a 3.6 Rubicon. Simply had enough emissions related issues with the 3.0. It is a great engine and I love it but the DEF issues and emission related check engine lights have turned me off on getting it in my Rubicon. The GC is currently at the dealer again getting NOX sensors replaced. Oh by the way they are removing the engine today to drill out the broken bolts in the turbo!





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MCJA

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I know others have already covered all of this - but I wanted to attempt to put it all in a "capstone" response.

If you're buying a diesel to "save on fuel costs" then you're doing it for the wrong reason. It would take a lot of miles and a long time to recoup the costs.

You need to separate the trim package (Sport, Sahara, Willys, Rubicon, etc.) from the engine choice (2.0T, 3.6L V6, EcoDiesel); they are separate decisions. The only correlation is whether you get a 4-door or 2-door - diesels aren't available on the 2-door; and manual or automatic transmission - diesels aren't available with a manual. So if you want a diesel, you're automatically looking at a 4-door automatic.

Primary reasons for getting the diesel:
  • If you tow a trailer. The diesel doesn't add any towing capacity over the gas V6 - but that's because of suspension, not because of powertrain. However, the torque of the diesel makes it pull much easier than its gas siblings. (This also affects transmission temperature.) There's a reason all 18-wheelers are diesels.
  • Using larger tires. Replacing your axles' ring and pinion gears will compensate for the increase in tire diameter. (e.g., numerically, your final drive ratio will be similar to stock). But that doesn't account for tire weight. Tire weight increases exponentially as radius increases. The low-end torque of the diesel helps overcome the rotational inertia of heavier tires.
  • Low speed off-roading. Diesels offer their highest torque at very low RPM - exactly the opposite of a gas engine. When performing low-speed off-roading (not mud or sand), you need high torque at low RPM - that will give you the grunt you need to get over obstacles without excessive drivetrain speed. Revving the engine to get torque and then applying that torque to a non-moving drivetrain is a great way to break drivetrain components (U-joints, axle shafts, driveshafts, gear teeth, etc.) Conversely, if you plan on playing in the mud and / or sand, then a gas engine would be the better option. In those cases, high RPMs and high tire speed are your friend.
  • Extended range. The diesel offers the highest range of any of the engines, namely because of the relatively high highway mileage. Don't confuse range with mileage though. A vehicle with poor mileage (low MPGs) could have an excellent range by have a really big gas tank, and vice versa. (A scooter gets 60+ MPG, but has a very limited range because it has such a small gas tank.) So if long road trips are your thing, and you want to stop less frequently, then higher range is better. Or, if overlanding is your thing, you may want the confidence of being able to tread farther from civilization on a single tank.
Diesels are all about torque. The diesel offers more torque than any of the gas options. If your use case(s) demand torque, then the diesel is your Huckleberry. Otherwise, save the money and get either of the gassers.

That said, ANY of the engines Jeep offers is a great option for most owners. They wouldn't offer them if they weren't suited to their "trail rated" standard, and if the market didn't support it.

PS: I love my EcoDiesel. I would do it again 100 times over.
 

AnnDee4444

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I have an interesting observation: The 3.0 Sport/Sahara actually has comparable torque available at the axle as gas Rubicon models (in low range & first gear).

Peak Torque1st gear ratioTransfer CaseDifferentialPeak axle torque
3.0 Rubicon4424.714:13.73:131,061
3.0 Sahara4424.712.72:13.73:121,121
3.6 Rubicon Auto2604.714:14.1:120,083
3.6 Rubicon Manual2605.134:14.1:121,874
2.0 Rubicon2954.714:14.1:122,787
 

DadJokes

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Just got back Monday from a week long trip from LA to Denver and back to visit my GF's parents over fathers day with mine and it was a blast to drive the whole way. Cruses nicely between 75-78 and absolutely loves climbing hills at those speeds with minimum downshifting so it's pretty much perfect as a road trip vehicle. On the way out to Denver we camped twice (first night in Manti-La Sal and the second night in McInnis Canyons to get some hiking in) and had about a 5-10 mph tailwind most of the way so I cruised at 78 while averaging 31mpg, however on the way back it was a 16 hour straight shot from Denver to LA and I was only able to maintain 75 comfortably while getting 25mpg since there was a steady 15-20mph headwind pretty much the whole way. Total cost of gas was only $220 and I still had 1/2 a tank left after filling up in Nevada.

I was only able to put about 15 miles of trail under it getting to campsites on the way out but aside from it being noticeably heavier in soft sand trails than anything else I've driven off road there wasn't any issue with that either.

Here are some of the pictures i took at both areas we camped at.
Manti-La Sal
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McInnis Canyons
50041117076_9be1214a99_z.jpg

50041116411_b34371b703_z.jpg

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So I’m thinking it might be a good thing to put the larger tires on to get some flotation back.
Looks like a great trip.
 
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Tank the Jeep

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I love my JLURD. I’m at 5400 miles. We recently went home to the N.C. mountains (near Asheville) from Charlotte. I filled up in South Carolina real close to the house. Paid less for diesel than N.C. gasoline. Reset the trip. on the interstate I set the cruise at 65mph and drove reasonable. when I pulled in the driveway that night, almost 250 miles at 31 mpg overall average. The tripometer showed 31.7 mpg. I’m running 37” BFG KO2s and the speedo was corrected. How could anyone complain about that? I hear the 2.0T is returning good fuel economy on stock tires. But can they match 31 mpg on 37”s? Probably not.
 

fjavier

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So I test drove yesterday the manual, the 3.6 automatic, and the diesel all back to back. I would say the diesel was my favorite, but not because of the torque, but because it felt more like a truck. It felt heavier, more sure-footed, and I enjoyed the sound of the engine. I would say that it wasn't a night and day difference when hitting the accelerator. The 3.6 was a higher-revving engine and it felt like u had to simply give it more gas to get going, but I did enjoy it. Between the manual and the automatic, I would say I liked the automatic more even though I've driven manuals for about 25 years. The reason was simply that the clutch felt too light for my preference and because I had to sit really close to the steering wheel since I am only 5'7".

When I got home after my test drive I reached out to a well know diesel tuner to ask them their opinions. I am posting my email and their response since many of you already own these jeeps and curious if you agree or disagree with the response.

Here is my original email:

I am considering buying a jeep wrangler diesel mainly as a daily driver but also as a weekend rock crawler and on rare occasions for a long overland trip. I am reaching out to you guys based on your reputation for putting out clean and performant diesel tunes which naturally means you know modern diesel engines well. I have several questions that hopefully you can answer.

1) Do you feel that the 3rd gen eco-diesel is a reliable engine based on the research you have done with your tuning?

2) Is the 3rd generation eco-diesel a good engine for slow rock crawling for several days. I know it has great torque, but it is my understanding when this diesel engine travels at slow almost idling speed that it can't burn soot efficiently leading to problems. Is this true? Can your tuning help out in this use case?

3) Are you aware of any potential issues were the exhaust emission system which runs extremely hot, is suddenly emerged in the water? I am concerned about water crossings and the effect it can have on the emission system.

4) If I will be doing my daily driving 75% in the city (start and stop traffic) and only 25% on the highway will this driving pattern lead to a lot of soot problems? If yes, will your tuning help with this pattern of driving?

5) When will you be releasing your tune for the Jeep Wrangler Diesel in California?

---- Response:
To your questions:

1) Hard to say at this point. The prior 2014-2019 engine was plagued with a number of mechanical issues in the bottom end of the engine, I don’t think FCA has sold enough of the Gen3 engines to really know if this has been solved or not.

2) The engine has okay torque but suffers a lot in its ability to deliver torque predictably and right when you press the pedal. The 442lb-ft # is what they advertise on paper but I’d say only in very limited situations can you actually get it. At some point it will need to do a regen while overlanding or rock-crawling, and this can’t be done at idle or very slow speeds. If you keep driving it in that situation, you’ll eventually end up in the condition where you have to get to a dealer for stationary regen. Hard to say if our tuning can definitely solve this right now.

3) The most delicate part is the DEF system, specifically the DEF injector. If it gets a blast of water while entering a creek or something, it could break off. When that happens you’ll get the “XX miles until engine will not restart” message. Not being able to start the Jeep in the middle of nowhere is a daunting proposition. I don’t think water splash onto a hot exhaust would be any worse than driving thru a large puddle on the road.

4) Diesels don’t like a primarily city-oriented drive cycle: you’ll constantly be in modes designed to heat up the exhaust (these modes make a lot of soot), and you’ll eventually face the same type of regen-necessary scenario like above. Our tuning will generally extend the regen intervals, but you still have to do one eventually.

5) Everything in California has to be emissions-compliant and CARB certified: this latter part adds a lot of time. It wouldn’t be until next summer at the earlier.

Honestly speaking given the price premium being charged for the diesel I’d take a hard look at the two gas engines given your primary use case of the Jeep.

Let us know if we can help with anything else.
 

oalvarez

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^ sounds grim.......can’t drive the thing thru a puddle or water crossing without fouling the DEF injector? sheesh.
 

fjavier

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So no one here who owns a diesel and goes offroading (water crossings, slow driving for several hours, etc) disagrees/agrees with the response from the diesel tuner I posted?
 

toolaide4fit

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Quick answer, I spoke to an expert that works with Jeep and frequently Jeep goes to him for answers. His advice to me was he thinks the diesel will be ok, but he buys new Jeeps and builds them to sell within the US and he builds and exports them also.

he told me to stay away from the 2.0 and the best choice is the 3.6.

Having said that, I have taken the chance on the diesel and he said he doesn’t think it will be a problem.

I absolutely love the diesel. I don’t particularly care about the gas mileage, but I wanted the torque for off-roading and it does not disappoint.
Lastly, the diesel in any trim has the same drive train as the othe trims for axles and gear ratio compared to non diesel trims. If you are going to do any serious off-roading look for a Rubicon Diesel.
 

DadJokes

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Quick answer, I spoke to an expert that works with Jeep and frequently Jeep goes to him for answers. His advice to me was he thinks the diesel will be ok, but he buys new Jeeps and builds them to sell within the US and he builds and exports them also.

he told me to stay away from the 2.0 and the best choice is the 3.6.

Having said that, I have taken the chance on the diesel and he said he doesn’t think it will be a problem.

I absolutely love the diesel. I don’t particularly care about the gas mileage, but I wanted the torque for off-roading and it does not disappoint.
Lastly, the diesel in any trim has the same drive train as the othe trims for axles and gear ratio compared to non diesel trims. If you are going to do any serious off-roading look for a Rubicon Diesel.
What failures of the 2.0 does he experience. I belong to a Wrangler 2.0 group. Nothing particular to the 2.0 of any frequency there. Curious...
 

toolaide4fit

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What failures of the 2.0 does he experience. I belong to a Wrangler 2.0 group. Nothing particular to the 2.0 of any frequency there. Curious...
One of the issues is the direct port injection. The lack of following the maintenance recommendations. His view point is the number issues has driven him to recommend the 3.6.

Please don’t take this as the engine is total garbage or anything. It was his recommendation to me if I had a choice. The discussion was about making sure I wasn’t making a $62,000 mistake getting the diesel. He said he didn’t buy a diesel to modify because from a business perspective he didn’t want to take a chance.

Said there were “issues” but his None Disclosure Agreement with FCA prevented him from talking about it. I said I know there were issues with EGR system. He didn’t confirm nor deny, but the EGR issues weren’t news.
 

Icewater

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One of the issues is the direct port injection. The lack of following the maintenance recommendations. His view point is the number issues has driven him to recommend the 3.6.

Please don’t take this as the engine is total garbage or anything. It was his recommendation to me if I had a choice. The discussion was about making sure I wasn’t making a $62,000 mistake getting the diesel. He said he didn’t buy a diesel to modify because from a business perspective he didn’t want to take a chance.

Said there were “issues” but his None Disclosure Agreement with FCA prevented him from talking about it. I said I know there were issues with EGR system. He didn’t confirm nor deny, but the EGR issues weren’t news.
I've been researching what to get between the Diesel and 3.6 over and over (my use case is similar to OP's), and after reading this thread was slightly leaning toward the 3.6. But then I heard that 2021 models have a new 3.6 etorque, have you heard anything regarding the new 3.6 addition? Would it be safer to just find a current 2020 3.6 instead of being shoehorned into the etorque ?
 

toolaide4fit

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I've been researching what to get between the Diesel and 3.6 over and over (my use case is similar to OP's), and after reading this thread was slightly leaning toward the 3.6. But then I heard that 2021 models have a new 3.6 etorque, have you heard anything regarding the new 3.6 addition? Would it be safer to just find a current 2020 3.6 instead of being shoehorned into the etorque ?
Haven’t heard anything about it. I would think you could get a great price on a 2020 rather than ordering a 2021. Best of luck!
 

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