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GM 3.1 V6 Reliability and Performance

I’m well aware of the reliability and performance of the 3800 engine, but what about the 3.1 found in a lot of late 90’s early 2000’s GM cars?

What are the impressions from those of you who have owned one and/or worked on them?

I had on in the 1999 Buck Century I owned. It needed the intake manifold gasket replaced once, but after that, it was a fine motor that gave me no problems. The car had 225,000 miles on it when I sold it, and it still started and ran fine.

As noted above the 3.1/3.4 engines had some lower intake gasket issues as did some other GM engines, but I think they are quite durable, reliable, and simple. A conventional V engine with a single camshaft and pushrods. Nothing sexy or exciting about them, just a reliable workhorse. I’d buy one.

Had one in my 98 Lumina, needed a intake, as most do, sooner or later. It was a great car and still ran fairly well when I sold it with 237k True story: the spark plugs were in the car for over 150k and still ran well and passed illinois smog testing.

Had one in my '92 Cutlass Ciera. Weren’t they just an underbore/understroke 3800? It was the best thing about that car–the transmission it was attached to was the worst thing! I recall that it had batch-fire, as opposed to sequential MPFI for the 3800, so the larger displacement engine got at least the MPG of the smaller 3.1.

That engine had been in continuous production forever, basically, and makes the argument for “proven technology”: manufacture a product, note where failures occur, adjust design as necessary. After a decade or so, you ought to have a design mostly free of glaring weaknesses.

I had a 3.1 in my new 5 speed 1992 Camaro RS. I drove it like I stole it. I gave it to my daughter after a few years and it’s still going strong. The only thing she’s done to it is have it painted and a new set of tires and wheels. The 3.1 is basically bulletproof in my opinion.

The 3.1 V6 is a 60 degrees-between-the-cylinder-banks motor derived from GM’s X-car engine of 2.8 liters. The 3800 V6 is a 90 degree cylinder angle motor derived from a 60’s era V8 later sold to British Leyland and used in lots of Brit cars. They also offered a 3.4 liter version that seemed noisy and rough for no reason. All are cam-in-block with pushrods with 2 valves per cylinder. Nothing fancy, proven technology.

The 3.1 was a pretty good motor as long as you fixed the intake gasket before any harm is done. Smooth with reasonable power. It will run a long time as other posters here have said. I’ve got a buddy who raced Berretta’s in the local circle track “compact” class for FWD small cars. His race cars used un-touched engines with well over 100,000 miles. Never had an engine fail.

^Ah. I stand corrected. Guess I was thinking of the 3.3 V6.

Yes @meanjoe75 fan that would have been the 3.3 V6 in that model year Olds. I try not to overthink an engine or where it was derived from. Many years ago I had my doubts about the god-awful ugly “slant 6” in my 1965 Dodge Dart that I drove back and forth to diesel school. That little inline 6 gave me a lesson in humility because it turned out to be bullet proof. When I joined the Air Force a couple of years later…one of my first jobs was pulling missiles in and out of the maintenance hangar with a “tug.” The tug was powered by a slant 6.

The Chrysler “slant six” should be taught to every engineering student as a perfect balance of attributes. Modern engines are wonderfully durable, but that engine from half a century ago shows you can get similar reliability without exotic techniques. I still (rarely) see an old Dart or Valiant around. The only car of its era I see more of are Mustangs, and they’ve needed more work to keep going.

Just a side note here about my old '65 Dodge Dart. I sold that Dart to a friend of mine when I joined the Air Force. He later wrecked it and the engine was sold to a saw mill. They used it for many years in some capacity (not sure) and I actually saw it when I bought lumber for an old barn that my dad was fixing. Talk about bulletproof. It’s one of the few engines that I actually miss from time to time.

@MarkM, Darts and Valiants (Dusters and Demons, too) were workhorse cars and very prone to rust (much like any 60’s car). They don’t have the enthusiast following or were they built in volumes like Mustangs of that era and sixes were never the favorites. There are fewer cars to save and fewer people to save them.

The slant 6 was a great motor, as was the Chevy 250 I-6 (and its variants, IMHO). Both motors couldn’t be abused enough to kill 'em. Pretty much the same for AMC’s I-6, too. The Ford small I-6’s couldn’t seem to hold their oil in. Now the Big Six, the 300 CID I-6 from Ford was a beast with endurance!

"Now the Big Six, the 300 CID I-6 from Ford was a beast with endurance! "

I saw one of these in a wheat combine. The gear-driven cam was one key to longevity.

They were common in their day, if not among the very best sellers. But what I was noting is that I still see them on the road sometimes, despite their age and not being collector favorites. Most of the ones I see likely spent their lives in California, so rust wasn’t an inevitable problem as elsewhere. There are more Mustangs because so many were sold and because early ones never went completely out of fashion, so people did what they needed to do to keep them going. Mustangs were very popular with my high school friends in the late seventies, despite being pretty well worn out by then. Nobody is going to those lengths to keep old Darts going, but their cockroach genes keep a few chugging along.

A friend managed to kill a slant-6 that he had in a Volare. (or was it an Aspen?) He bought the car used, for a song, with a ton of rust and about 130K miles as I recall. He ran it out of oil and it developed a rod knock as a result. He continued to drive it with the rod pounding so hard it shook the car and you couldn’t hear yourself think over the noise of it. I have to wonder if there was even any bearing left at that point. After about 2 weeks of this it finally threw a rod and knocked a hole in the block just over the starter, where part of the twisted rod could be found. As was his philosophy back in those days, he went to take his license plates and battery and abandon the car to the city. I went with him just for kicks. Amazingly the thing started when we tried and ran as an I-5, though it was spewing oil everywhere.

Speaking of cockroach genes, I still see the occasional K-car chugging along, probably about one every month or so.

^ Hah. I had a Volare with the slant 6 for my first car. Fond memories of the old beast.

I had driver training in a Volare, though the four. With an automatic it was so slow we couldn’t have gotten in any trouble if we had tried. At home we had the similarly slow B210 automatic. Two of the most underpowered cars of the 1970s, and I had the privilege of driving both. Kids today have it so easy, with their eight second 0-60 times even in mundane economy cars. Those slugs each took well over 20 seconds.

Yes, the slant six was a wonderful engine, the long runners of the intake manifold gave it more torque at lower rpms than larger competing engines and the fact that it had only 4 main bearing instead if 7 gave it less friction whih helped fuel economy and power. They even used it in fairly good sized moving vans. When Nascar held compact car races at Daytona in the spring of 1960, Chrysler unloaded 12 “spaceship” Valiants with 170 cubic inch slant sixes with a 4 barrel carb and went 132 mph on the straightaway and finished 1-11th and 13th. A Volvo finished 12th.
The 13th place Valiant had rolled on the road course portion of the track.

“A Volvo finished 12th.”

That might have been Volvo’s best performance

Definitely broke the mold

They’re probably scratching their heads, wondering what went wrong since then