Jeep Wrangler EcoDiesel First Drive: By popular demand

Wrangler fans will mark 2019 as the year Jeep fulfilled their two most frequent requests: a new Jeep pickup truck and a diesel engine. The Jeep Gladiator pickup debuted in April, the first Jeep truck since 1992.

The second shoe is about to drop when the third-generation turbocharged V-6 EcoDiesel goes on sale later this fall, available in all four models of the 2020 Jeep Wrangler Unlimited. Two-door Wranglers won’t get the diesel mill, according to Jeep execs, but a diesel-powered Gladiator should be available sometime later next year, perhaps as a 2021 model.

Fiat Chrysler Automobiles hosted a press event in and around Utah’s Zion National Park earlier this month. During the day, Jeep executives explained the many changes required to fit the V-6 engine under the Wrangler hood and to withstand the rigors of the off-road rock-crawling capabilities that define the Wrangler brand. The engine, rated at a modest 260 horsepower and a thoroughly immodest 442 pound-feet of torque, generates its own forces that the Wrangler needs to handle.

After the presentation, we drove 2020 Jeep Unlimited Saharas for the relatively staid (well, mostly) pavement driving in the morning and 2020 Jeep Unlimited Rubicons for off-road fun in desert dunes and up, down, over, and around steep rock formations.

Why diesel? What’s it for?

In light of the Volkswagen Dieselgate scandal, the obvious question is, why add a diesel to the Wrangler lineup? Consumers may clamor for a diesel, but how will the EcoDiesel benefit the platform? Towing is one possibility – truck drivers who tow heavy loads often prefer diesel engines for their torque – but the Wrangler specification sheets disproved the towing notion. All 4-door Wranglers are rated for a maximum 3,500-pound towing capacity, regardless of the engine.

I posed the tough questions to Mauro Puglia, FCA’s Chief Engineer – EcoDiesel Engine. My first question was about fuel economy, and Puglia didn’t have an answer, or at least not one that he could share, because EPA fuel economy ratings are still pending.

I then asked Puglia about the primary benefits Jeep buyers will enjoy with the diesel engine that can overcome the questions raised by Dieselgate. I suggested fuel economy, engine durability, and towing as possibilities (this was before we had the spec sheets). Puglia dismissed towing, and while giving the nod to the potential for diesel engines to last longer than gas engines, he said the two most significant benefits are fuel economy and driving range.

Unfortunately, due to the EPA-pending status, Puglia couldn’t pin specific numbers on fuel economy or range. Still, he did say something we heard repeated by other FCA personnel during the event. According to the Jeep people, the Wrangler with the EcoDiesel engine has the highest fuel economy and the longest range of any previous Wrangler.

So, we’ll have to wait for the specifics, which should be available soon, but the apparent confidence of all FCA staff repeated the economy and range claims, usually with a big smile, lead me to believe we’ll see good numbers.

That Jeeps with the EcoDiesel engine will have the longest range is especially significant because diesel-powered Jeeps will have 18.3-gallon fuel tanks while 4-door Wranglers with the 3.6-liter V-6 Pentastar engine and 2.0-liter Turbo inline-4 motor have 21.5-gallon tanks. Also, while he didn’t tell us the exact weight gain, Kevin Metz, the Jeep Wrangler Senior Brand Manager, said the diesel engine added about 400 pounds to the vehicle.

Specifications

The 3.0-liter EcoDiesel V-6 engine, with its 260-hp and 442 lb.-ft. of torque, will have engine stop-start (ESS) tech as a standard feature. The diesel will only be available with an automatic transmission. Because of the engine’s high torque levels, Jeep recalibrated a Torque-Flight 8HP75 eight-speed automatic with low shift points and created more than 40 shift maps or optimized fuel economy and performance.

All EcoDiesel Jeeps will have third-generation Dana 44 front and rear axles with a 3.73 axle ratio. Sport, Sport S, and Sahara models will use Jeep’s Command-Trac part-time two-speed transfer case with a 2.72:1 low-range gear ratio. The off-road-centric Rubicon will use a Rock-Trac two-speed transfer case with a 4.0:1 low-range gear ratio.

Overall, approximately 80% of the third-generation EcoDiesel engine is brand new, leaving little that carried over from the previous generation, Puglia told the group. Many of the changes or adaptations were made to improve economy, performance, or range.

Jeep engineers also designed components to reduce the diesel engine’s noise, vibration, and harshness (NVH), Puglia said. Offsetting the piston pin 0.3 millimeters from the centerline and using lightweight sandwiched polymer/metal for the lower portion of the two-piece oil sump were two changes made in the interest of NVH.

The Diesel’s engine block is cast compacted graphite iron for greater strength, lighter weight, and less vibration than conventional cast iron. Other significant changes for the new generation include a new water-cooled turbocharger, redesigned cylinder head intake ports, a dual-loop exhaust gas recirculation system, redesigned pistons with carbon coating, a dual vacuum pump system with mechanical and electric pumps, and much more.

EcoDiesel-powered Wrangler will carry a 5.1-gallon diesel exhaust fluid (DEF) tank behind the regular fuel tank. DEF is injected into the exhaust to convert harmful emissions to water and nitrogen. Owners will refill the DEF tank approximately every 10,000 miles, the same mileage required for oil changes.

On-road driving impressions

I drove a 2020 Jeep Wrangler Unlimited Sahara with the new EcoDiesel engine approximately 100 miles, about one-quarter of which was slowly driving through Zion National Park and back. So, for the most part, I didn’t press the engine very hard.

I didn’t hear any typical diesel engine clatter except for two times when I went through entrance and exit checkpoints in and out of the park, but even then it was a slight noise. Nothing at all like the loud knocking you hear when your neighbor fires up his large pickup diesel in the morning.

The Sahara I drove in the morning had a soft top. When I was outside Zion National Park, on my way to Sand Hollow State Park for lunch followed by off-road testing, I was able to assess the diesel’s highway pulling-power on several sweeping but reasonable grades. In short, it hauls.

The first time I was able to open it up a bit on the highway, I noticed a whistling noise from the soft top at 82 mph. When the whistling didn’t go away with just a little more speed, I took up to 100 mph to see if I could out-drive the sound. The Wrangler has a 106 mph top end, so I didn’t go any faster, and I then proceeded (somewhat) more leisurely.

When I told Kevin Metz, the Wrangler Senior Brand Manager, about the whistling, he was surprised. At the end of the day, when we got back in Saharas to drive back to our hotel, I picked a different, random vehicle again with a soft top, and there was no whistling noise at any speed, which satisfied me that my earlier experience was a one-off.

I didn’t perform any acceleration tests with the EcoDiesel Saharas. It’s not that type of vehicle. However, any time we needed or just asked for extra power for fun research purposes, the diesel delivered.

Off-road driving impressions

The off-road driving experience with a 2020 Jeep Wrangler with the EcoDiesel engine was anything but staid. While I was laughing and hollering, I drove the Jeep on loose desert sand paths with nature-made speed bumps large enough to slow me down, but the diesel-powered Rubicon never faltered or stalled.

The more significant test where speeds of less than one mph were more the rule. I drove the Rubicon up and over extremely steep rock formations, aided by a crew of trail guides who carefully monitored driving paths and turns. I was amazed by the Jeep’s capabilities.

The engine showed its stuff during the rock crawling, moving at ever-so-slow speeds using the EcoDiesel’s wide, 1,400-RPM-to-3,000-RPM maximum torque power band surely and steadily. We were operating in the desert at temperatures in the mid to high 70s, and even at the slow speeds with lap after lap on the crawling course, the EcoDiesel never failed.

Will the EcoDiesel be worth the extra expense?

In addition to EPA fuel economy ratings, driving range estimates, and precise vehicle weight with the EcoDiesel engine, Jeep hasn’t announced pricing for the diesel engine. Metz said the price difference between a Jeep Unlimited with the V-6 gas-powered engine and the V-6 diesel would be “about $4,000,” but we don’t know if that figure includes related and required upgrades or other changes.

When I asked Puglia, the EcoDiesel engineer, about the breakeven point, the number of miles owners will typically need to travel before the improved fuel economy made up for the higher engine cost, he wouldn’t give a figure or even a guess. He stressed, however, that the added range afforded by the EcoDiesel engine would be the most important factor for many people for whom the extra dollar cost would not be a significant concern.

There’s no question that Wranglers, like the Gladiator pickup truck versions, are expensive vehicles. Discounts are rare and usually unnecessary because, for years and possibly decades, Jeep has sold every Wrangler manufactured. It’s challenging to find a Wrangler Unlimited on a dealers lot for less than $40,000, and Rubicons fully-tricked out with factory options can easily top $60,000. Once the EcoDiesel-powered Unlimiteds begin showing up at dealers, we may see Jeeps with $70,00 to $75,000 pricing sheets after add-ons.

In the end only a Jeep is a Jeep. Wranglers and Gladiators with the EcoDiesel engine likely won’t last on dealer lots for long. The many changes FCA made in the many Wrangler systems and parts to accommodate the diesel engine should make it a better vehicle overall.