The Jeep Wrangler finally has a diesel engine: here's what's great about it

Tuesday, 26 November 2019

Jeep has finally put a diesel engine in the legendary Wrangler and it actually makes it even better off road.

There's never been a diesel-powered Jeep Wrangler in the USA before, but after 20 minutes behind the wheel of the new 2020 Wrangler EcoDiesel, it's hard not to ask yourself, 'What took 'em so long?'

Developing 600Nm of torque at just 1,400rpm (and 194kW of power at 3,600rpm), the 3.0-litre diesel V6 is a natural for clambering over boulders and through soft sand - just what Wrangler owners love. Add surprisingly quiet operation and an expected 30 per cent improvement in fuel economy - it should approach, maybe achieve, 7.8L/100km on the highway - and it's easy to foresee the EcoDiesel becoming the premier Wrangler powertrain.

Jeep reworked its 3.0-litre V6 significantly compared with the version that just debuted in the USA in the Ram 1500 pickup with changes that included sealing for water fording and sound insulation.

It's only taken 33 years (or 74 if you count the CJ Jeep before it), but the Wrangler finally gets a diesel engine in the USA.

The EcoDiesel weighs about 180kg more than a comparable Wrangler with a petrol V6. About 170kg of that is because of the engine, which, among other differences, has an iron block that's heavier than the petrol engine's block, and is needed to deal with the higher stress on a diesel.

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The big torque of the diesel engine makes the Wrangler an even more formidable rock crawler.

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A day spent driving Wrangler EcoDiesels on highways, country roads on rugged canyon trails in southern Utah and the diesel provided plenty of power and proved as adept at fast highway cruising as scaling rock.

Jeep asks a US$3,250 premium for the diesel, meaning it would be a rather expensive option here in NZ.

Farmers and other folks who tow heavy loads like diesel because the engines develop plenty of torque at low engine speeds.

Generating lots of it at 1,400 engine rpm, like FCA's third-generation EcoDiesel does, means you don't have to rev the engine madly to pull a heavy load; smooth steady pressure on the accelerator does the trick.

Jeep is only making the diesel V6 available in the four-door Unlimited model.

That trait is just as useful when you're easing over a rockfall as it is when you're hauling a horse trailer.

Add the Wrangler's rugged suspension, 70:1 crawl ratio and off-road tires, and the EcoDiesel made easy work of grades up to 30 degrees, loose rock and soft sand.

The Wrangler has a 44-degree approach angle. That's the steepest incline the vehicle can take without scraping its front bumper. Its departure angle, the maximum incline it can drive off without scraping the rear, is 37 degrees.

Official EPA fuel economy ratings are expected any day, but Jeep executives promise more than 800km highway range, enough for a day's off-roading and a long ride home. We averaged a shockingly good 6.6L/100km in several hours of on-road driving.

The diesel's 70-litre fuel tank is smaller than petrol models because the Jeep has a 19-litre tank of urea to treat its exhaust. Drivers should only need to refill the urea every 16,000km.

One of the trade-offs for diesel's power and fuel economy is generally noise and vibration. The engines are inherently louder and shakier than a comparable gasoline engine.

Jeep engineers used hydraulic engine mounts to keep vibration from reaching the passenger compartment - even when the engine auto-stopped to save fuel at traffic lights. New carpet and sound deadening foams between engine and occupants locked out most noise, even driving in a soft-top Wrangler.

The diesel is available across the Wrangler lineup, but it's not cheap - a US$3,250 (NZ$5,000) premium over the 3.6L V6. There is no word on what the premium would be if the diesel even comes to New Zealand, although a spokesperson for the local distributor only said they 'didn't have any on order currently.'

Jeep will only offer the diesel with four-door Wranglers with four-wheel drive and an eight-speed automatic transmission. The four-door Wrangler, called the Wrangler Unlimited, accounts for 90 per cent of Wrangler sales.

While you can get a base Wrangler with the diesel in the US, executives expect most will be high-end Sahara or Rubicon models.

Which means a Wrangler EcoDiesel will never be cheap if it comes to New Zealand, with the Wrangler Unlimited Sport S starting the range at NZ$72,990 and the Rubicon topping it at NZ$92,990, meaning a diesel-powered Rubicon Unlimited could easily top $100,000.

Of course, while this is the first diesel engine in the Wrangler for its home market, the previous model was available with a wheezy VM Motori turbo diesel four-cylinder engine in export markets including new Zealand. Underpowered for the Wrangler's bulk, the diesel didn't meet US emission standards, so was never sold there.