Same Engine, Different Trucks: 1986 GMC S-15 vs 1986 Jeep Comanche

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Welcome back! Today, we have a pair of pickup trucks that are the same model year, both compact, both four-wheel-drive, both manual, and have the exact same engine – but come from different manufacturers. How does that work? We’ll get to that in a minute. First let’s check in on yesterday’s dinosaurs:

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Ooh, a tight race! But it looks like it’s the Thunderbird by a mere ten votes as of now. Yes, I know it actually shows eleven. I used to be able to see the results without voting, but it won’t let me anymore, so one vote for the T-Bird is me. Usually it doesn’t matter, and usually I end up picking the losing car anyway.

Now then: It’s common knowledge that automakers share engines, and have for a long time. Often smaller or struggling automakers will buy engines from one of the bigger companies to spare themselves the cost of developing their own engine. Think Lotus and their use of Ford, and now Toyota, powerplants, or Iso and their Chevy V8s. And even big automakers will buy engines from one another to fill in holes in their lineups or make do while they develop a new engine of their own, like Chrysler using VW and Peugeot engines for the Omni/Horizon, or GM tapping Honda for engines and transmissions for the Saturn Vue.

Back in the 1980s, and continuing well into this century, GM’s 60-degree V6 was the Judy Greer of engines: it appeared in everything. First introduced in the X-body cars in 1980, it hung on for 25 years in various forms in the US, and another five years in China after that. It powered family sedans, pickup trucks, SUVs, pony cars, minivans, mid-engine sports cars – you name it. And for a while, in the mid-1980s, GM sold them to AMC for use in the Cherokee, Wagoneer, and Comanche before David’s favorite engine was ready for prime time.

[Editor’s note: The 2.8-liter V6 was an absolute pile in the Jeep XJ. From what I’ve read, it rarely made it past 150,000 miles without major work. Honestly, people don’t realize how crappy early XJs were if you didn’t get the AMC four-cylinder with an automatic. The Peugeot-sourced five-speed was horrendous, the GM V6 sucked, the front axle vacuum disconnect would eventually get fussy, and I’m sure there are some other early-XJ faults that I’m not thinking of. The interiors were fantastic, though. -DT].

And that’s how we arrive here, checking out two beat-up old pickup trucks from different corporations with interchangeable engines.

1986 GMC S-15 – $2,500

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Engine/drivetrain: 2.8 liter V6, 5 speed manual, part-time 4WD

Location: Denver, CO

Odometer reading: 124,000 miles

Runs/drives? Well, according to the ad

The Chevy S-10 and GMC S-15 pickups appeared in 1982, replacing the Isuzu-built Chevy LUV compact pickup. The 2.8 liter V6 was an option from the very start, as an upgrade over an Isuzu-built 1.9 liter 4 cylinder carried over from the LUV. I’ve only ever seen one 1.9-engined S-10 in the wild; I think most buyers opted for the V6. Later GM 2.0 and 2.5 liter fours were more popular, but not a lot.

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This particular S-15 is a pretty fancy model anyway, with an extended cab and 4WD, and two-tone paint. I bet it was a pretty sharp-looking truck in its day, actually. The small-truck boom was in full swing by 1986, with more and more people opting for a pickup as their primary vehicle, and a heavily-optioned S-15 like this would have been a good choice.

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Its glory days are behind it, but it’s not in terrible shape. The interior is intact, and I don’t see much rust to speak of, though there are some dents and dings, and it’s pretty faded. The seller says it runs well and recently passed an emissions test, no small feat for a carbureted engine from the Reagan years. That engine is backed by a five-speed stick and a shift-on-the-fly 4WD transfer case with a low range.

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And can I just add that two-tone trucks really need to make a comeback? It’s such a great look.

1986 Jeep Comanche – $2,500

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Engine/drivetrain: Also a 2.8 liter V6, 5 speed manual, part-time 4WD

Location: Also Denver, CO

Odometer reading: 162,000 miles

Runs/drives? Yes, but needs brake work

AMC was late to the small-pickup party, but in their defense, they were almost broke. The success of the XJ Cherokee gave them the perfect starting point for a small truck… with a little work. The unibody Cherokee lacked the frame rails that usually make up the backbone of a truck, so AMC grafted basically half of a traditional frame onto half of a Cherokee body to create the Comanche.

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This first-year Comanche has a seven-foot-long bed, a foot longer than a typical small truck bed, but still a foot shorter than a full-size long bed, or the mid-sized Dodge Dakota that would appear a year later. Jeep offered a short bed as well, but due to the unusual frame arrangement, never developed an extended-cab variant. This would be the only year that the Comanche came with the GM V6 under the hood; in 1987 the 4.0 arrived and life got a lot better.

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This Comanche is in reasonably good shape, but with a lot more wear and tear inside than the GMC has. But it also has that cool Jeep three-spoke steering wheel. Outside, there is some rust and very faded paint, but that just adds character to an old truck. This 2.8 also runs well, but the truck needs some brake work before it can be driven reliably. The seller also includes some not-yet-installed parts, including an alternator and a carb rebuild kit. No word on whether these parts are necessary or not, but it’s nice that they’re there.

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With a solid front axle, this truck is likely a little rougher-riding on road and a little more capable off-road than the GMC, but neither one is going to ride like a Cadillac or climb hills like a billy goat. But for general beat-up-old-truck duty, either one will work.

The GM 60 degree V6 isn’t without its faults; head and intake manifold gasket failures aren’t uncommon, and its performance in small trucks was only so-so, especially the early carbureted versions like these. But parts are as common as sand at a beach, and cheap. And today, it’s your only engine choice. So what’ll it be: GMC, or Jeep?

Quiz Maker

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78 Responses

  1. My first purchase in 89 was a 87 Chevy S10 Blazer 4×4 ,owned for 17 years up and down California to the deserts to the mountains , towed my dad’s new boat when his F250 has issues , the 2.8 was weak but gotta say it was pretty reliable

  2. The GMC won just based on pictures of the condition.

    Anything that moves under it’s own power for under $3000 is jump at it in these times. In the before times, these would have been under 1k.

  3. I picked the GMC, but I have an emotional attachment to the Jeep. I picked up a ’87 Blue 4×4 “sport truck” short bed, 4cyl/4speed at an auction in 1990 for $3000. It was a nice truck, the 4wd was awesome where I went to school in Canton, NY. Also the only speeding ticket I ever got (on campus) LOL.

    But the Jeep is too rough, I heard the 2.8’s at this time used rope for the rear main seal? Junk GM, Junk!

    1. well let’s be a bit more honest about that statement, Rope seals were used on all sorts off engines back in the day, not just GM, Jeep used them on the first CJ motors, this kind of reply indicates how little your knowledge of old Iron is.

  4. Gotta go with the GMC today. My reasoning is that I have seen a lot of these with small block swaps done, so a heart transplant should be fairly straight-forward. I am yanking that garbage 2.8 the second I take ownership. That, and the condition helps.

  5. I agree that we need more two-tone paint jobs on trucks. Hell, I’d settle for just more real honest-to-God colors! My theory is that it faded away for awhile due to the body lines not really lending themselves to that paint scheme. Take the ’97-’04 F150 for example. Where do you put the part line on those swoopy bodies? GM held onto it through 2006(?). That two-tone paint stopped at the tailgate which bugs the crap out of me. I like the effort on the current Ford Heritage editions, but they could have gone with a bolder scheme. My favorite trucks for two-tone are the late 60’s – late 80’s GM trucks. The body lines are perfect for that scheme!

  6. No matter the platform, that engine sucked more than Sasha Grey, and not in a good way. It would get pulled on either vehicle.

    With that in mind, its about aesthetics and what you’d rather look at, and honestly the S-15 was never an attractive truck, even as a single cab. Couple that fact with the Jeep turbines on the Comanche?

    Jeep, please.

      1. except they also fit fine in that Jeep and the solid front axle means it can be made to properly wheel, just wish it had a proper frame. maybe not, the Jeep frames from that era were known to rust terribly as well. hmm

  7. David is really underselling how awful the 2.8 is in all it’s forms.
    And when I’m telling you that David, the man who describes a car with no floors and half a frame rail left as ‘a little rusty,’ is underselling it?
    Run. Run far away.

      1. As a life-long GM truck diehard fan … Yeah, the 2.8 is piece of shit. I’d still buy that S-15 in a heartbeat (of America! … Sorry, couldn’t resist, even if it’s a GMC and not a Chevy), and swap it when it surely dies soon. I miss my S-10s. They were such good trucks.

      2. I mean, I can be acerbic and cranky in text, but wow. Certainly hope you didn’t misinterpret me at some point. I reserve my “die in a fire, here, I brought gas” for people who say things like whether LGBTQ+ people are allowed to live or even exist is up for debate. (It is not up for debate or discussion.)
        I’m more ‘threaten to smack upside the head’ before launching into the ‘no that is NOT how you fix the oiling system’ rant, or to take one away to a loving home that will blow up the engine in somebody else’s cell doing stupid stuff (hmm, twincharged on an unsalted stock block? Yeah, sounds like a good idea.) By the way, don’t leave rubber ‘rolled up newspaper’ squeaky dog toys around, they’re my favorite implement. Bad! We do not ignore torque specs!

        Like this:
        Anybody who thinks the GM 2.8 engine is even an engine should be forced to spend the rest of their lives driving one. Or attempting to between major repairs. Like seriously, the LH7 is so utterly awful they tried to erase it from history by reusing LH7 for a 1.6L diesel from Europe. And that was the ‘good’ 2.8.
        I mean for fuck’s sake, how do you design an engine so badly that coolant in the mains and completely blowing out the coolant system is a common problem?! Oh right. You spend all the time trying to make what may be the worst MAF and EGR setup ever work enough to pass emissions.

        1. saddest part is back in the day, it was the desirable engine in the Fiero and the Z24 Cavalier Kind of make you wonder if the FI of say a Fiero would have worked better in either of these two trucks. My issue with both of these is the carburetor

      3. Not as many Kool-Aid drinkers on the 2.8 Turd as with the 360.
        But I’m not a fan of the AMC 360 either, with one Grand Cherokee going thru two different heads in a year.
        The one 2.8I had, was fine(low powered, but never failed me), but GM rust killed the suspension mounts so off to the crusher that Corsica

        1. … so I shouldn’t point out to you that the Grand Cherokee never in it’s life for even one millisecond had the AMC 360?

          Nope. It did not. Was not even considered.

          AMC 4.0, Chrysler LA block 5.2/318, and the glorious one-year only 5.9 Magnum. The 5.2 was… not a great decision.
          Followed by the absolute dogshit, not-even-half-assed, no value even as a fucking boat anchor 3.7 and 4.7. And the only reason I know it wasn’t one of those is because you said it went through cylinder heads, no mention of dropped valves or thrown rods.

    1. I recall the Buick version having oiling issues. Our auto shop class rebuilt 3 of these during my 2 years, at least that’s what I remember, it was 37 years ago.
      The aftermarket 2 tone schemes for modern trucks are pretty great. If only I could get my EV pickup, I’d do that.

  8. I picked the Jeep because If I am going to have a permanently immobilized vehicle sitting in my front yard, the Jeep truck just looks way cooler. I drove the S-10’s for Pizza Driver duty in college, and they really sucked on every level. I believe their 2.5 engine red-lined at like 4,200 RPM’s(or something that low). The Frames flexed side-ways, so you were stuck on twigs. ZERO acceleration, with poor Gas mileage thrown in. The 5 speed trans was sloppy shifting, and the gear ratios seemed to be picked at random(maybe from other different units assembled in the same factory).
    At least with the Jeep Truck, you can pray to find a wrecked XJ Cherokee with low miles, to transplant its 4.0L “Forever Engine”. It’s ashamed the bed is trashed, and it has the 2.8 Chevy Citation engine, other wise it would be a landslide vote in favor of the Comanche.

  9. For my money I am going with the gmc. I am a Ford guy who would go Toyota if I had no other option so both of these are not my cup of tea. And as much as I love a single cab long bed in these smaller trucks a 6’2″ guy needs the room of the extended cab. Also, either one you buy needs an engine swap to get rid of that garbage V6.

  10. I can echo DT’s comments about the weakness of the 2.8 in a Cherokee – I had an 86, with the 5 speed. I didn’t find the gearbox to be a problem, mine shifted just fine but…….the 4 cyl was rated at 125 hp and the V-6 at 135, but they were 135 of the smallest ponies I ever drove. That thing was weak!

  11. I like the Jeep just because of the looks. I was never a fan of the S10/S15. The Jeep has (IMHO) much better curb appeal but is probably so rusty underneath that it’ll split in two after hitting a big enough pothole. The motor’s got to go, but knowing my luck DT would sell me the 4.0 I’d want to swap in.

  12. Nobody mentioned yet that the GMC is sitting on rims commonly found on Jeeps?
    Yeah, in addition to sharing drivetrain parts, these vehicles share wheel lug patterns. It’s very common to see an S10/S15/Ranger/Explorer/XJ/MJ/YJ/ZJ/etc. rolling on rims from a competing brand.

    Those ones appear to be GM rims, but they bear a strong resemblance to rims available on this era of XJ:×600/products/1059/4884/1512-jeep-wrangler-rim-15-inch-alloy-stock-oem-wheel-aly01512u10__01794.1601596102.jpg?c=2

    (I wish I could post a picture…)

    Or see the third entry on this page:

  13. I’m on team Jeep, only because an XJ would be the donor of a heart transplant ASAP to this poor Comanche recipient. I always wanted a Comanche 4.0 little pickup, but by the time I had the money and a place for one, they’re pretty much all gone.

  14. The Jeep does it for me. I don’t know what they sold like, but have never known them to be common, whereas GM trucks are a dime a dozen and don’t hold any particular appeal to me. Sure the condition is better on the S15, but styling-wise the Jeep looked good then and still looks good now. Bonus points for being relatively uncommon.

  15. Going to go with the S-15. I’ve actually been casually looking for an S-10 or S-15 to do a custom minitruck thing with. Square S-Series are hard to come by in usable condition in my neck of the woods, so I’ve extended my search to include the less desirable 1995-2012 version, which seem to be one of the only vehicles these days not actually worth much.

    I also have a bit of a nostalgia twinge for the GMC. My brother ordered an S-10 extended cab new in 1988. It was the highlight of his life and the beginning of a long, slow slide that continues to this day. He loved that truck; red, 2wd extended cab with the ever-so-slightly-better 4.3 V6 / automatic combo, vinyl interior, and the rubber floor liner. He (I) did some minor modifications to it, installing a tonneau cover and an air dam with foglights. Eventually he wrecked it, causing my dad to buy it out from him, get it repaired, and sell it. Every subsequent car has been a little older and a little more clapped out.

    1. I have an 03 with the 2.2. 170k and it goes ok. $500 truck and I have $1300 in it including purchase. And probably 30 hours. It belonged to a pest control co down the street and it didn’t get driven in the winter. Pretty slow but hey, cheap. Watch for weird lights in the dash like abs, brake, bad odo. Had mine redone for $275 as the processor chip goes bad. Buddy told me that in this gen you need to start with the 4.3 so the motor mounts work. Got 7k miles so far in a year and has been my daily since May.

  16. One of my cousins had a S-15 with that 2.8. Ran OK for a while but then one day it wouldn’t fire. Next day it would run normally. Another day it would fire, run fine for a while and then run like crap. Sometimes it would die and sometimes it would improve. After trying everything he could think of, he yanked it and tore it down. When he pulled off the main bearing caps, and took the crank out, it was broken in two. Apparently sometimes it would move enough that it wouldn’t run, and sometimes after cranking it the sections would align and it would run again.
    Long story to say I voted for neither.

    1. 100% neither. My parents had an S-10 Blazer with the 2.8 and an Eagle Premiere. Both were massively unreliable and my dad only used them to get 3 miles to the train station.

      I became an “only buy Japanese cars” person for a long, long time.

  17. This was neat. Same year, same shitty engine (so we don’t need to argue about it), same general equipment, same price. I pick the GMC because I like the color better, it seems to be in somewhat better condition, and yes, I do want a bit more cab. That was the only thing I disliked about my beloved old $7500 Hilux (well, along with the lack of AC): the regular cab meant my toolbox had to ride around in the bed. I’m 6’2″ so I need the seat shoved all the way back, and it’s a bummer when I can’t stash stuff behind it.

  18. So, I know the 2.8 was a dog, however it’s not as *entirely* bad as everybody claims. Starting in ‘87 with the changeover to EFI, GM did make some internal changes to combat the 2.8’s appetite for head gaskets. It helped, as later 2.8s weren’t nearly As fragile. That said, the 2.8 was still woefully underpowered for a v6, and I’d never voluntarily own one. Given the choice between these two trucks I’d take the GMC, but with the mindset that it would probably be a 4.3 swap candidate. Now THAT was a good Minitruck engine.

  19. My dad had a Comanche that had a horrible yellow/white 2-tone paint job and wouldn’t go into 4wd, but I regret to this day not buying it from him. So I came to this poll with the intention of voting for the Jeep, but after looking at the pictures…I kinda want that GMC.

  20. I had the 2.8 carb version in an ’85 celebrity eurosport wagon. I wasn’t super familiar with cars then like I am today, but suffice it to say, that if you wanted to start it up when the temperature was 50ºF or below, you needed to perform a very specific rain dance thrice (perfectly, I might add) blow a few ounces of ether down it’s carbed throat and then hope and pray that you push the accelerator about 12mm down when starting – not a millimeter more or less, as it always required a tiny bit of gas to start… but too much, and the engine floods and you have to wait for enough of the condensation of fuel in the pistons to re-vaporize (again, below 50º this could take a while).

    More awesome was that it’s listed 0-60 time wasn’t a number – it was just a word, which was “sometimes”

    Despite being power nothing (weight reduction!), it accelerated about as quickly as tar pitch through a narrow funnel. Torque was great, so seemingly would work well in the truck.

    MY PICK: the GMC, it’s road ready and the interior isn’t one tenth as shitty as the Jeep’s. And any Toyota “Pickup” from that era, in a similar drivable condition is going to go for double either of these, but would be worth the extra.

  21. Even with the awful engine I was all Comanche until I saw that side profile picture with the big dent and rust in the bed. Hard to find a replacement bed these days. I could see it end up being a flatbed wheeler with a V8 though… but as a former S10 owner the S15 won me here.

  22. My head says GMC, but my heart says Jeep. I’ve always loved the Comanche pick-up since I was a kid for absolutely no rational reason. That GMC looks like it’s been well used by the beat to hell rear wheel well and bent bed railing, but that kind of gives it some character. That interior is in pretty good shape too. The Jeep is a Comanche with a really long bed for its class. I guess that I’m just going to have to take the advice of Roxette and listen to my heart. Jeep.

  23. If the Comanche was a bit less long, this would be a Shortbox Showdown.

    I’ll defend the 2.8. I had an 85 S15 Jimmy, carbed 2.8 4 speed 4×4, that I bought for a grand in 1998 and drove the wheels off of. No power at all, but handled weekly 200-mile freeway trips, idled silently, and was the best friend a lonely car idiot could have during a rough time. It finally passed when the rust monster detached the rear window for the second time, but parts of it lived on in a truly horrible 91 S15 truck (4.3, 5 spd, 4×4, tetanus).

  24. Not every choice has to make sense. Some might choose the Chevy, others the Jeep, but regardless there is no logical reason to opt one way or the other.

    In that spirit, make mine the Jeep. Sure, the interior is worse for the wear, but the remaining seat fabric pattern is delightful. Plus, I like how it looks (those lines) and I LOVE those AMC-style turbine wheels. They’re beautiful.

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