Vacuum Leaks Suck: 1985 Chevy S-10 Blazer vs 1987 Isuzu P’up Spacecab

Sbsd 3 21 2024
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Welcome back! Today we’re taking a visit back to the bad old days of feedback carburetors, and looking at two otherwise-cool trucks that are suffering from carb problems and/or vacuum leaks. Which one is worth untangling the black spaghetti for? That’s what we’re here to find out.

Yesterday I gave you a tough choice between two cool vehicles. Both cars had lots of fans, and several of you said you’d take both if you could, but in the end, the big tall Mitsubishi took home the win. Score one for sport, and utility.

I think I agree, for what it’s worth. I do love those old Volvos, but it occurs to me I already have a car with a pushrod 1.8 liter four, a four-speed stick, and twin SUs. Do I really need another? I mean, I don’t need an upright Japanese SUV either, but I have a feeling I’d get more use out of it. And I did really love our old Nissan Pathfinder.

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Now, those who are too young to remember the malaise era might not realize what the real villain of that era was. It wasn’t catalytic converters, or the switch to SAE net horsepower ratings, or five-mile-per-hour bumpers. No, the face of true evil in those days was the electronic feedback carburetor and all the miles of vacuum hoses connecting it to various power-sucking emissions devices like EGR valves and air-injection pumps. Take an already lean-running engine, give it a vacuum leak, and you’ll want to drive the thing off a cliff, only you can’t, because it won’t stay idling. Or has no power under acceleration. Or something.

Both of today’s trucks are so afflicted, I’m sorry to say. But knowing that they’ll both need a weekend of replacing every hose and gasket you can think of, we can assess the rest of their respective merits and see which one you think is worth the trouble.

1985 Chevrolet S-10 Blazer – $3,500

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Engine/drivetrain: 2.8 liter overhead valve V6, four-speed automatic, part-time 4WD

Location: Chico, CA

Odometer reading: 80,000 miles

Operational status: Runs and drives, but hesitates unless you floor it

I have always had a soft spot for the two-door S-10 Blazer. It’s such a clean design, and it’s just the right size, practical, and tough. The only thing that could have made it better is a removable rear section of the top like the old full-size Blazers had. The sweet spot for these came a couple of years after this one was built, when the 4.3 liter V6 became available; these 2.8s were a little anemic, especially with an automatic. But I can only feature what I find for sale, so we’re stuck with the small motor.

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Fun fact about the 2.8 liter V6 in these: You access the oil filter through the driver’s side wheel well. A cup-type filter wrench, two long extensions, and a ratchet, and it slips right out above the left front tire. The rest of the truck isn’t quite so easy to service, but it isn’t terrible either. If this Blazer were one year newer, it would have throttle-body fuel injection, but sadly this one is fed by a two-barrel carb, which seems to be the cause of most of its running woes.

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It could use a little upholstery work too, but I haven’t seen a mid-Eighties GM product with a perfect interior since the mid-Eighties. Even with a rip in the seat, I remember these as being pretty comfortable inside. Sadly, that comfort is somewhat compromised by non-functional air conditioning. The seller, of course, claims that it only “needs to be recharged.” Uh-huh.

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The paint’s a little faded, but I don’t see any rust. And it’s two-tone! We need more two-tone cars. I mean, more color variety in general would be good, but two colors on one car? Now that’s living.

1987 Isuzu P’Up Spacecab – $2,800

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Engine/drivetrain: 2.3-liter overhead cam inline 4, four-speed automatic, RWD

Location: Hemet, CA

Odometer reading: 155,000 miles

Operational status: Technically runs and drives, but has brittle vacuum and fuel lines

Isuzu was always kind of an also-ran in the small truck wars. After years of selling Isuzu pickups as Chevy LUVs, Isuzu brought over its trucks under its own name to compete with Chevy’s S-10. Years later, the roles were reversed, when Isuzu sold a rebadged S-10 as the Hombre. In between, Isuzu pickups were known by the adorable contraction “P’up.”

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Every small truck maker sold an extended-cab variant, but Isuzu’s “Spacecab” was special. Not only was it extra long, it was extra tall as well, with a raised roofline for a couple extra inches of headroom. Every little bit of room counts in these small trucks, and the taller roof probably made the inward-facing jump seats in the Spacecab almost livable.

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The P’up is powered by Isuzu’s 2.3-liter overhead cam four, in this case backed by an automatic transmission. Automatics are rare in small trucks of this era, especially Japanese trucks, and I know some of you are rolling your eyes in disgust right now. But for a little runabout truck, it doesn’t really matter that much. It will be a little sluggish, but it will still haul stuff home from the garden center just fine.

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Or it will, once you replace a bunch of perished rubber vacuum and fuel lines under the hood. This truck has been off the road for a while, and as you know, cars don’t like to sit. Rubber hoses get hard and brittle, and while imminent failure of vacuum lines will ruin your day and cause drivability issues, potential fuel leaks are dangerous. At least they’re not high-pressure lines, since it’s carbureted.

These days, we take easy starting, smooth idling, and hesitation-free acceleration for granted. Fuel injection is a wonderful thing, and it has now been thirty years since the last carbureted vehicle was sold in the US – coincidentally, an Isuzu pickup. But plenty of old carbureted cars are still running around, and that means the dark art of carburetor tuning, including tracking down vacuum leaks, is still good to know. And vacuum hose is still available by the foot at any good auto parts store. So which one of these is worth the hassle of sorting out?

(Image credits: Craigslist sellers)

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65 thoughts on “Vacuum Leaks Suck: 1985 Chevy S-10 Blazer vs 1987 Isuzu P’up Spacecab

  1. Going with the Isuzu because anything called a “Spacecab” is something I want to drive! Also the seller definitely put more care into cleaning the thing up for the ad, so maybe the thing has been reasonably well cared for. And I don’t think I could stand sitting in the red carpeted Bronco interior for more than a couple of minutes. (Is that shag carpeting?)

  2. Had a 92 S10 Blazer “Tahoe” through college. It was my “why won’t it just die” vehicle. Looking back now though it was a great, simple vehicle. GM seats back then were great for my 8 hour trip one way to college and it always made it. Rot finally got it but still look back fondly.

    That said, went with the Spacecab because of the 2.8 and it would be way cooler to show up to a C&C in.

    *Note that the 4.3 also had the fender mounted oil filter. It was the one area where it didn’t rust!

  3. I went with the Isuzu because( In Joe Isuzu voice) “its engine produces over 500 hp and gets great mileage with Fuel Economy of 125 Miles Per Gallon And does 0-60 in 2.1 seconds!! ” 😉

  4. The Blazer is a handsome vehicle with a combo of features that is long-gone – two door/two-tone. The 2.8 sucks even when working properly, but I’ll fix it and run it for a bit until I can source a cheap LS truck motor. The Isuzu is nice, but not digging the “helmet” look.

  5. My first car was an ’86 P’up in light blue with the 5 speed. Tough little guy, I can tell you that the extra headroom was much appreciated. There was room for a 4″ speaker at the top each corner!

    1. I had a next gen P’up, regular cab. Much more room than in a S-10 or Ranger of the same year (and I was 6’5″ at the time. Yes, age shrinkage is real.)

  6. Vacuum leaks can often be found by taking a volatile spray like break cleaner and spray everything down at idle. When you find the leak the rpms will pick up.

    1. Yep, works very well. Don’t go crazy with the brake cleaner around the engine though…a co-worker lit a Ford Tempo on fire that way haha

  7. I went with the Blazer just because of the body style. The mileage is attractive, unless it’s rolled once, which would put them on about equal footing. You could maybe revive the Isuzu easier, but I think the Chevy is more worth putting effort into.

  8. I’ll take the Spacecab and devote a weekend. I can remember my dad showing me how to find a vacuum leak with those old airline headphones, the plastic kind with 2 tubes. Of course those days are long gone and the smoke test works better anyway. Sometimes it’s just easier to replace them all and not worry about when the next one will happen. Cheap small truck wins for me.

  9. I had an 87 2.8 S10 Tahoe years back, so I’m not exactly enthusiastic about the Blazer. But I’ll take it over an automatic 4-cylinder 80s mini-truck any day

  10. I always kinda liked the Spacecab look. Sure it would be better in 4WD and stick shift and the later rounder face version, but we have to play the cards we’re dealt.

  11. I voted for the Spacecab. They are awesome 🙂

    Even though the Blazer has a cooler interior, and yes, red interiors are fucking awesome, I still voted for the other one because small Japanese pickups are the best ones.

  12. That P’up is amazing. I have a buddy who used to own one and he swore up and down how absolutely tough it was. Based on his stories, I’d believe it. Even though we tend to look down on automatics here, this one is equipped with the TH-200 (not to be confused with the 200R4), which was a solid unit. It was used to back up the GM 231 V6, 305 V8, and an iteration of it in the Grand National. In fact, it even has a bit of a following among certain groups of drag racers.

    1. The 200 behind the GM engine you mentioned was known for being weak. Behind an Isuzu engine it should be fine due to less torque.

      I bought a next-gen P’up because of how reliable this generation was when used by the delivery business I work for.

      1. I think there’s a little confusion, mostly because there was some muddy nomenclature. The TH-200 is the known good unit, whereas the 200R4 you mentioned is the weak one. At least, that’s according to the internets, so take that for what it’s worth. 😉

  13. I have a soft-spot for 2-door SUVs, especially body-on-frame, so Blazer it is. Plus, as JDE points out, a junkyard 5.3 swap is not a herculean effort.

  14. Blazer. While I like the Isuzu, the Spacecab was odd looking when new, and is odd looking now. Plus, I had a friend with an ’86 Blazer with the fuel injected 2.8L and the inverse of the paint scheme above (white on top/bottom, red in the middle). It was rather fun to drive, as much as something like it can be anyway, and impressive in how much stuff it could hold. The thing wasn’t fast, but it was surprisingly reliable even past 230,000 miles.

  15. That Blazer brings back so many memories. My mom’s ’89 had the 4.3 V6 and was pretty loaded up: digital dash, power windows and locks, the fancy cassette stereo, and the nicer cloth upholstery, with fuzzy ribbed velour on the seat bolsters. I’ve never seen a Blazer (or any other Chevy, for that matter) with that weird steering wheel before, though it’s obviously original. My mom’s was two-tone, too, white with gold rockers and (painted!) bumpers.

    Whoever wrote in that ad that the Blazer is “almost 40 years old,” though, needs to shut their lying mouth. That’s like saying *I’m* almost…oh, crap.

    1. That’s the standard steering wheel for 1983-1985, though I think there was an optional wheel with two spokes angled downward. In 1986 the steering wheel was changed to have the round horn button with the two straight metal spokes coming off of the bottom of it. I think they kept that until like 1991 or 1992 when the S10 Blazer got the four spoke steering wheel from the fullsize trucks.

  16. I firmly believe that “neither” is basically a cop-out in the sophie’s choice construct we’re voting in.

    However, I am failing to find purchasing appeal in either of these vehicles with the issues they come with. They will be dubiously reliable, unsafe due to simple age, and (to me, anyway) offer no real interest outside of body-type practicality. Neither vehicle has enough performance/curiosity/weirdness points to get me excited beyond their basic function, and there isn’t enough basic functionality present to justify owning them.

    I’d be shocked if you couldn’t find something better in their respective classes at the same price points.

    1. Seeing one in person does not change that impression. It’s an ungainly truck.

      We went with the Blazer; surely there’s a pick-n-pull 4.3 that will drop in without too much effort?

  17. Blazer – I know a 5.3 and 4LslippyE fits in that engine bay and i do also dig the 2 door blazer styling. I also know the wheelbase is close to a Scout 2 and many of those need a body donor anyway. So bob’s your uncle!

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