The Jeep Comanche is one of the more forgettable models from America’s favorite off-road automaker. The humble pickup popped up for a few years, made a few sales, and then Jeep fled the truck market entirely for several decades. Even more obscure, though, is the rare diesel version. The oil-burning Comanche promised amazing fuel economy and savings, only to disappear shortly after it hit the market.
America has always had a weird situationship with diesel. On the one hand, Ford and GM sell plenty of Power Stroke and Duramax engines every year. Meanwhile, in the Ram world, people go nuts for anything with a big ol’ Cummins in it. Outside of these mainstream truck applications, though, the oily fuel has never quite caught on.
Indeed, that was the problem Jeep faced in the 1980s. Along with the rest of the Big Three, it tried to jump on the diesel bandwagon with fuel-sipping engines, only to find that they didn’t quite connect with the market. Let’s dive into the tale of the diesel Jeep trucks that vanished almost as soon as they appeared.
The French Connection
The 1970s were a tough time for American motorists. Oil crises raged and left drivers lining up at gas stations to fill their tanks, while prices climbed ever higher. This created the conditions for diesel’s rise. It had long been the preserve of trucking and agriculture, but now, it had potential as a new fuel for mainstream use.
Diesel’s higher energy density and ability to run at higher compression ratios meant it could offer fuel economy beyond any gas engine. This left automakers scrambling to find diesel engines to add to their fleets. With the 1980s around the corner, the game was on. GM rushed out a converted gas engine that soon became an unmitigated disaster. Dodge grabbed a diesel from Mitsubishi and imported some compact turbodiesels to boot. Even International Harvester got in on the action with a turbodiesel Scout, just before it collapsed.
Meanwhile, Jeep was running late to the party. The diesel craze that started in the late 1970s had already faltered by the early 1980s, with GM’s disastrous Oldsmobile V8 doing huge damage to the reputation fo diesel engines as a whole. Still, come 1985, Jeep was finally ready. It had a diesel ready for the showroom floor.
Given the partnership between AMC and Renault in the 1980s, Jeep’s choice of diesel powerplant was easy. It grabbed a variant of the Douvrin engine off the shelf. The engine family featured both gasoline and diesel variants, with Jeep choosing a 2.1-liter turbodiesel known as the Renault J8S for its greater power output. The all-aluminum engine weighed just 331 pounds and relied on cast iron cylinder liners for durability. It achieved a compression ratio of 21.5:1 in diesel form.
Despite forced induction, the French-designed four-cylinder wasn’t exactly a powerhouse. It put out just 85 horsepower and 132 lb-ft of torque. In the power stakes, it was well down on the standard 2.5-liter gasoline four which offered 117 horsepower and 135 pound-feet of torque. This was also at the time that Jeep was offering a 2.8-liter gasoline V6 as an upgrade option, though it was questionable—it offered less power than the gasoline four at just 115 hp, but a small lift up to 150 pound-feet of torque.
Unlike many of its American contemporaries, the Renault diesel used an overhead cam design and used a timing belt rather than a chain. This made it smoother and quieter, at least in theory, but it also meant more frequent maintenance, as the belt needed changing every 50,000 miles. The J8S would eventually be known for head gasket and head bolt failures, too. No surprise, as it was often thrashed to haul 6,000-pound Winnebagos down the interstate for hours at a time. Notably, Jeep also kitted the engine with an intercooler, differentiating it from some less-sophisticated turbodiesels then on the market. As was common at the time, the engine was fed via a mechanical fuel pump, with no electronic controls.
The engine was actually quite popular around the world, and the J8S ended up in a whole lot of Renault sedans, as well as the sporty Fuego and the Espace, Trafic and Master vans. The J8S also found homes in the Winnebago LeSharo and Itasca Phasar RVs, both of which were built on the Renault Trafic platform.
Jeep debuted the diesel on the 1985 Jeep Cherokee and the related Wagoneer. When the Comanche rolled around in 1986, based on the XJ platform, it made perfect sense to include it on the pickup, too. Years after the competition had tried diesel—and some had failed—Jeep was giving it a go.
[Mercedes’s note: Curiously, this wasn’t even the first time Jeep offered a diesel to civilians. The first was a Perkins diesel in the CJ-5 back in 1961, but that wasn’t really a pickup truck. – MS]
What the diesel lacked in muscle, it made up for in efficiency. The diesel Comanche could achieve up to 31 mpg on the highway and 28 mpg around the city in two-wheel-drive models—impressive numbers for a pickup in the late 1980s. Even the four-wheel-drive models could do 29 mpg highway and 28 mpg around the city. These figures were a solid jump above the 2.5-liter four-cylinder gas engine, which performed as poorly as 23 mpg in the city. Jeep’s optional 2.8-liter gasoline V6 did even worse, achieving just 17 mpg with barely any more power than the four-cylinder engine.
On its initial launch in the Cherokee, Jeep paired the diesel with either a three-speed automatic or a five-speed manual transmission. However, it was rather underpowered for the 3,300-pound SUV. Thus, when it appeared on the Comanche, Jeep only offered it with a manual transmission.
Despite the horsepower deficit, however, it wasn’t a terrible performer. According to Diesel World, contemporary magazine tests had the diesel donk largely keeping up with the gassers. Reportedly, Four Wheeler timed a diesel Cherokee in the zero-to-60 mph sprint at 17.31 seconds with 4.10 gearing, and 20.1 seconds with the 3.73 final drive. Meanwhile, the 2.8-liter V6 achieved 19.8 seconds with the 3.73 gearing—suggesting the diesel was slower, but maybe only by a hair. None were quick, but that was never the point of the Cherokee or Comanche anyway.
Gone Tomorrow
Ultimately, the diesel Comanche disappeared after just two years. Jeep’s compact pickup entered production in 1985 for the 1986 model year, and the turbodiesel was mentioned in all the brochures. However, by 1988, the Renault diesel was no longer available—and it was the same story for the XJ Cherokee, too. That is, in the US—the engine stuck around until 1994 for the European market.
In the US, several factors contributed to its demise. Gas prices stabilized by the late 1980s, with buyers in turn taking less interest in the fuel efficiency offered by diesel models. There was also still a hangover from GM’s early diesel efforts, which had seen huge class-action lawsuits and much negative press coverage.
There was also the matter of cost. In 1985, the diesel engine was a $1,124 option on the Cherokee, compared to just $300 for the V6. That was a big chunk of change for a vehicle that started at under $10,000. For that money, you were getting improved fuel economy, but it would take you some time to make up the difference. For many, the higher price likely spoiled a lot of the appeal of the otherwise thrifty diesel.
We don’t have exact numbers on how many Comanches rolled out the door with diesel power. For the Cherokee, though, Diesel World suggests that just 3,343 XJ Cherokees got the engine in 1985, along with 329 Wagoneers. In that same year, Jeep built 98,877 Cherokees and 13,501 Wagoneers. Ultimately, the take rate was somewhere below 4%. It’s no surprise Jeep decided to cancel the engine given the lack of customer demand. In any case, with only a handful built over the two years or so they were in production, they are now incredibly rare today.
The diesel Comanche was late to the party, and the Cherokee hadn’t exactly shown up early itself. It wasn’t the end of the story for Jeep, though. The company would later dance with diesel again, several times in fact. It even built a new diesel pickup in the form of the Jeep Gladiator, which rocked a 3.0-liter turbodiesel V6 good for 260 horsepower and 442 pound-feet of torque. Despite the prodigious twist and good efficiency, though, it similarly failed to find an audience. Jeep announced it was exiting production in 2023, just two years after its debut.
But in 1986, America just wasn’t ready for a small diesel pickup; at least, not one wearing the storied Jeep badge. The Big Three ended up unlocking the secret to building popular diesels, with high-displacement engines in full-sized trucks. Meanwhile, Jeep never quite found a diesel that excited their rusted-on fans in the home country, and the world moved on.
Image credits: Jeep, A1AA1A – CC BY-SA 4.0, Bring a Trailer
Top graphic: Jeep, Renault
I remember when Jeep started exporting Cherokees to Spain with a diesel engine. Jesus, that was a long time ago.
While I wouldn’t want the diesel variant, I have loved the looks of the Comanche for a long time. Definitely all the truck I’d ever need.
The main problem is that none of the big three ever tried to own their diesel IP and refine and grow it. You have designs licensed from other manufacturers which can help in the short term but they end up missing out on the long game.
If the big 3 had a small format (for mid to large cars/suvs) and a heavy duty variant for the heavy duty stuff, and perhaps most importantly they would refine and tweak their designs as the years progressed there is no reason they wouldn’t have the equivalent of an LS but for diesel. I thought diesel was supposed to be less complicated to build and maintain. Are they insanely hard to design vs petrol or something?
Forgettable? I don’t think so. Good examples still command a good bit of money. They have the highly regarded Cherokee under pinnings. I think the Comanche lines hold up to this day and would love to own one with the rock solid inline 6.
A big failure for 2025 Jeep is not building a follow up to the Comanche & instead, the went for the overbloated and over priced Gladiator.
Hi Everyone, I’ve been reading The Autopian for a long time and have just registered to comment on this thread. Over the years I’ve bought about 4 new jeeps and 4 used jeeps. Then I switched to Toyota Tacoma Pro models for 16 years. The 2019 Tacoma Pro had a high-revving engine that made a lot of sound but not much speed and the transmission was always in too high of a gear. Jeep didn’t make a truck so it was Tacoma 4×4 or nothing for the narrow trails I take in Arizona/California.
When I saw the Gladiator arrive on the market I was very interested and read a lot about it. When they introduced the diesel in the Gladiator I decided to get one
“when the time was right”. We all know about the inflation and high interest rates in 2023, but Jeep took the Diesel from the Wrangler and then announced they would eliminate the Diesel from the Gladiator as well. In early 2023, with high interest rates and with dealers still adding $5,000 market adjustments to the sticker price the time was as right as it’d ever be because of the upcoming elimination of the Diesel engine.
The local dealer said they didn’t have any diesels and would NEVER have any unless I ordered one. The bright side is that if I ordered it, it would only be $70,000 MSRP and no extra market adjustment added. I custom ordered a Rubicon with the Diesel engine and it is fantastic. It has tremendous power and I am thrilled. I’ve had it since March 2023 and have put a little over 40,000 miles on it with zero trouble. I can’t emphasize enough about how much power it has. I’ve had no issues at all with it these past 40K miles and I like it so much better than the 2019 Toyota Tacoma Pro!
I do take it offroad often.
In the interest of completeness the Forward Control Jeep did have several diesel versions but none were commercially sold in the US. The USMC version of the FC had a 3 cylinder 2 stroke Cerliat diesel and the Mahindra FC-260 and Viasa SV 430 used the Perkins P4.
I had a 1988 Comanche for twenty years. It was the four cylinder 2.5l version. Great truck for me because I was a carpenter and did a lot of renovation projects in town and the Comanche was big enough to haul most of what I needed yet small enough to maneuver and park in town, and got decent mileage for the era. Never clocked it but it wouldn’t surprise me if that 4 cylinder took twenty seconds to get to 60. My blazing fast by comparison Triumph GT6 that I drove in college took over 12 seconds.
It was also an amazing capable 4 wheeler. I used it for hunting in the woods over roadless terrain and through deep mud and snow. I once put it in low range and pulled a wrecker out that was stuck in the mud at a job site. (the wrecker had come to pull me out and got stuck after it did, and I got the Comanche in a spot where it could get some traction and returned the favor.
I’m going to start this comment with a note: what I’m about to write isn’t an apples to apples comparison, however I find it interesting nonetheless.
The diesel Comanche is listed in the article as 21/28mpg, achieved from 2.1l of turbo diesel power(?). That’s great for a pickup from that era.
Except…
Vehicles with GM’s 6.2 diesel could strangely do better. Again, I’m admitting this is not apples to apples, but from my CUCV-owning days, I recall M1009s (the Blazer) averaged 26/30 mpg. Real world, it wasn’t unusual for guys to hover around 28mpg in daily driving capacities. I’d have thought that the Blazer would be heavier than a Comanche, less aerodynamic, lacked OD (TH400 with 3.08s were the only drivetrain choice), and yet somehow it used less fuel despite having an engine that displaced roughly 3x as much as the Comanche. I’d wager the M1009 was quicker too but I don’t think there were ever any published 0-60 times.
Are we just going to gloss over the fact that the Archer brothers used to race Commanches in the SCCA RaceTruck series?
Not diesels, of course, but that whole series was pretty nuts and somehow everyone forgot about it.
I think you missed last week’s article on this.
https://www.theautopian.com/the-rare-jeep-street-comanche-and-the-man-trying-to-keep-the-memory-alive/
You are correct, I missed that completely! Thanks for the link.
Chrysler Corporation purchased AMC/Jeep in 1987. This deal being in the works was almost certainly a major factor in the discontinuation of the Renault diesel in the Comanche, since Renault was a 46% owner of AMC/Jeep prior to the sale. Other Renault products such as the Alliance & Encore were discontinued in the US around this time, for that reason.
Renault disengaged from the US after a political deal between the two governments. Basically they coughed 2 billion into bringing whatever american automotive corporation they were working with (AMC, Jeep, you name it) and were then told ok, now we want them back. Renault was at least part government owned back then, so it was an easy decision. Not sure what France got back out of it, but it has remained in history as yet another case of pay for it with (French) taxpayer money then give it away.
If memory serves, it wasn’t just the engine – Renault had some considerable input in the development of the Cherokee altogether.
Renault proudly imported Jeep in Europe, then just in France, for a few more years. The Diesel Cherokees were their main bread and butter. Then Chrysler took that away too and created Chrysler France, which was again considered a national scandal – more humiliating that when Volvo went to VW for engines a few years later, after having worked with Renault for a while.
“If memory serves, it wasn’t just the engine – Renault had some considerable input in the development of the Cherokee altogether.”
Such as the front seats – which were on a pedestal with a curved track so you would rock/recline the seats back.
They came right out of then-current Renaults.
The diesel Comanche is extremely rare. Some sources put the number sold at around 20. I am an active member of the Comanche Club forum owning a 4.0L model myself. The forum members have managed to account for 3 or 4 Renault turbo diesel Comanches still on the road.
One owner was astoundingly lucky to spot one of the diesel engines in a scrap heap on a truck going to a junk yard. They flagged down the driver and procured the engine. It was in great shape as if it was a spare engine that hadn’t been installed in a vehicle.
Holy crap! I figured they were rare but that’s an absurdly low production total.
Always leave it to forums to scour out an idea of how many are left/ever existed.
The J8S 2.1 diesel was derived from the J7R gas engine, an engine I know all too well because it’s the one that powered my Renault Espace Quadra From Hell (RIP). I may have gotten some mild PTSD just glancing at that engine bay, and the J7R in the Espace wasn’t even mounted longitudinally.
Such a mixed bag of fun and horrible memories, that one.
The best reason to buy the diesel XJ/MJ is for an engine swap in a state like California where a diesel doesn’t have to visit the smog station. I knew a couple guys who were running Chevy V8’s and 4.3L V6s in these.
These Renault diesels weren’t very reliable or long-lived.
What I wish AMC/Jeep would have done would have been to spec the XJ with the 2.8 GM Gas V6 and with the Olds Diesel V6. The Olds V6 even had aluminum heads for saving weight (also was the first use of lost-foam aluminum casting). The Olds V6 diesel was also much better built and more reliable (especially in 1985) vs. the Olds V8 diesels.
I mean, they were already sourcing one engine from GM, might as well have done the other?
They inherited the reliability of the gas engine they were based on.
After the Oldsmobile debacle, American manufacturers universally recognized they shouldn’t try making Diesel passenger car and minitruck engines. And they mostly had foreign partners to supply such engines.
GM put Isuzu Diesels into Chevettes and S-10’s, along with the Buick Opel by Isuzu, obviously.
Ford put Mazda Diesels into Escorts, Tempos, and Rangers.
Chrysler didn’t really do passenger cars with Diesels, but before the tie-in with Cummins, some D- and W-series pickups got Mitsubishi Diesels.
International used Nissan Diesels (although I don’t think there was any tie-in, they just bought engines off the shelf.)
And AMC used Renault engines.
A friend of mine had one of those diesel Escorts back in the 80s. He was so proud of the fuel economy, but man, that thing was dog slow.
Ford also used a BMW turbo diesel in some Lincolns.
And those Renault engines were… based on gasoline engine architecture. Really makes it go full circle, considering the Oldsmibile V8 diesel debalce.
Well, so were the VW Diesel engines, but they did the “conversion” *well*.
Non-US market XJs later also received a 2.5 VM Motori 425 diesel, very similar to the one in David’s Chrysler minivan.
The older Renault diesel is indeed slower, but considered to be more reliable.
Both of them are too slow for US highways.
The best diesel Jeeps in my opinion are the 2.7 inline-5 CRD WJs and the 3.0 V6 CRD WKs, both powerplants sourced from Mercedes.
The V6 did 0-60 in TWENTY seconds?? I don’t understand, I’ve driven an S-10 with the 2.8, and it was slow, but nowhere near THAT slow
On the Comanche forums, the 2.8 V6 is considered by everyone to be the worst engine offered in the MJ. It’s suspected that GM sold the dog and crap engines off of the assembly line to AMC for the Jeeps. Most have problems and many owners choose to engine swap to a later larger displacement GM V6 or swap in the far superior AMC 2.5L gas 4 cylinder which was fuel injected unlike the GM V6. Some crazy people even move the firewall to fit the Jeep 4.0L that was offered in 87+ Comanches.
Do auto makers really want to sabotage a product that badly? Seems too petty.
If these had come with a shrubbery in the bed they would have sold like hotcakes…
Ni!!!
20 second 0-60 times were something. Even then that was not a great sales pitch. Not too many people look back on many of the early 80’s jeep motors fondly.
“ It even built a new diesel pickup in the form of the Jeep Gladiator, which rocked a 3.0-liter turbodiesel V6 good for 260 horsepower and 442 pound-feet of torque. Despite the prodigious twist and good efficiency, though, it similarly failed to find an audience.”
That 3L V6 ecodiesel was great… until you had to fix it. And apparently they had to be fixed a lot. See this I Do Cars youtube video on one of these engines.
https://www.youtube.com/watch?v=2lSHuzkv_RU
I had a Comanche for a couple of years, though not a diesel. This was a genuinely great little truck if you could avoid rust. Sadly, mine had not had its cabin drain plugs pulled ever by the time it came into my hands and its unibody cab frame was on its last legs. I said goodbye when a solid Scrambler came my way. I always wanted a CJ8 and loved mine, but, honestly, the Comanche was the better pickup. If I could find a rust free example today, I wouldn’t hesitate to re-engine it with a Cummins R2.8 Turbodiesel and drive off into the sunset. I might even keep the original mill if I happened across the Renault diesel. Sadly, the Comanche was one small pickup too many for Chrysler once the Dakota dropped and was a hit.