: Let's talk about the 4.3L V6.



I~LUV~Caddys8792
02-01-11, 11:54 PM
What do you guys think of GM's trusty 4.3L V6?

I've got mixed feelings. First of all, I've got one in my '00 Astro that will pass a quarter million miles tomorrow or Thursday, and it's been very, very reliable, needing no major work, so it's got that going for it. On the other hand, it's kinda course and isn't very powerful (torquey, but not powerful) It has less horsepower than the 3800 Series II, but a little more torque. I know it's based off the 350, but was it's goal always to be a torquey V6 made for trucks? It's got a great deal of low end torque, especially right off idle, so it doesn't take much throttle to get the Astro up and moving, especially with it weighing in around 6,000 lbs, but once you're out of first gear, acceleration is lethargic (0-60 in 15 seconds when loaded up, around 11 seconds when empty)

They seem to be pretty reliable engines. Do they have an issue with intake gaskets like most other GM engines from the '90s? Mine are original, and they've never leaked. I know oil cooler lines are an issue on the S10s and Blazers, but that's not the engines fault, that's hardware.

Aron9000
02-02-11, 12:18 AM
I'd say they're a reliable workhorse, but in terms of power output and fuel efficiency, they are pretty crappy. They don't get any better fuel economy in full size trucks vs those with a 5.0 or 5.7 V8. In the S-10 they are kind of thirsty as well, but power output in that smaller truck is quite good and its a worlds better motor than the rough, course, and underpowered 4 cylinders the s10 offered.

Really I think they're pretty good in the blazers and s-10's, but I hate them in the full size trucks. Although the engine bay in an s10/blazer with the 4.3 is VERY TIGHT and a PITA

I~LUV~Caddys8792
02-02-11, 12:21 AM
I wonder why they didn't do like Ford or Chrysler and offer a V8 in the Blazer and S10.

Aron9000
02-02-11, 01:29 AM
I wonder why they didn't do like Ford or Chrysler and offer a V8 in the Blazer and S10.

Honestly I think the s-10 Blazer is a piss poor vehicle compared to a Tahoe, at least on the used market. I don't know how close they were priced when new, but IMO the Tahoe is a much nicer truck and doesn't drink the gas much worse than a Blazer.

I~LUV~Caddys8792
02-02-11, 01:46 AM
I'd agree with that statement, except for the 00-01 Tahoes v. 00-01 Blazer LT's or Trailblazers. I never cared for the early GMT800 SUV's, and those LT/Trailblazers were very nicely equipped.

Aron9000
02-02-11, 01:51 AM
^ Oh yeah, those Trailblazers were a completely different animal compared to the old S-10 Blazer. Just much more substantial truck, and a lot more reliable as well.

I actually like the early GMT-800's over the later version. Mainly the steering wheel looked a lot cooler, I loved how the spokes all the way down to the airbag hub were leather wrapped, felt really nice and didn't have all those damn buttons on it(I despise steering wheel buttons).

As for the 4.3 V6, I felt like it really wasn't adequate in the heavy Astro, especially since those things are always loaded down with cargo, people, or pulling a trailer. I'm sure every mechanic cusses up a storm when they see an Astro or full size van roll into their bay, it can't be helped that they are also a PITA to service.

Jesda
02-02-11, 01:56 AM
I think people take better care of full-size GM trucks compared to the midsizers.

ga_etc
02-02-11, 02:01 AM
I like the 4.3, but I think you already knew this from having this conversation on the phone. It's a workhorse motor that all but refuses to die. The power and torque output is very similar to that of the N/A 3800, but all of the torque is down low where you need it in a truck/van.

I think the S10/Blazer never got a V8 option is because Chevy had them placed as a mid-market, more economical alternative for those who didn't specifically need the full size alternative.

Sevillian273
02-02-11, 07:50 AM
It's the only V6 whos sound I can tolerate with anything less than a stock muffler.

Playdrv4me
02-02-11, 07:59 AM
The lack of steering wheel audio controls on the early GMT800 was really freaking annoying. Especially when Jeep had already had them since the mid '90s. I thought the 2003 interior redesign of all the GMT800s REALLY brought those trucks into the 20th century. It must have felt particularly irritating to have paid 50 large for a 2002 Escalade, only to have been one-upped with better seats, a better steering wheel, Xenon headlights and true electronic climate control the following year.

I~LUV~Caddys8792
02-02-11, 09:22 AM
Actually Aron, the Trailblazer I was referring to was the one made in 99-00, it was the fancy option package for the S10 Blazer, not the whole new model that rolled out in 2001. I had confused the years.

drewsdeville
02-02-11, 10:27 AM
To compare the 3800 and the 4.3 in terms of power is a little silly. While the max numbers are similar, the powerbands are completely different.

From what I noticed with 3800's I've driven, they are a little light on power on the low end of things but pick up nicely midrange and beyond. The 4.3, however, almost feels V8 like, with decent power nearly everywhere in it's RPM range. It's a popular choice for smaller sub-19' i/o sport boats for that reason. A sub-200hp 4.3 has no problem getting some pretty heavy fiberglass boats on plane in short order (when correctly prop'd)

Unfortunately, just about every vehicle the 4.3 was stuffed (yes, stuffed) into was a nightmare to maintain. It's amazing how difficult something as simple as a plug change is on a lot of 4.3's. One reason I laugh when people try to convince me maintenance is always RWD's advantage. Pfft.

Stingroo
02-02-11, 10:41 AM
Oh god. Plug change... Astro van.

I'm terrified already.

Sevillian273
02-02-11, 02:02 PM
Aww cmon, it cant be as bad as #2, 4, 6, and 8 on a 4.x. I did an S10 once, it was pretty standard and an Astro has the removable engine cover in the cabin.

drewsdeville
02-02-11, 02:05 PM
Really? You find the 4.X to be difficult? I mean, I do have slender arms, but still...the 4.X is pretty accessible for a fwd with a V engine, in my opinion. Just wire up the heater hoses out of the way and it's pretty smooth sailing.

The way that the 4.3 was wedged into the GMT330's is amazing. The 4 cylinders and 2.8's weren't too bad, but the 4.3 is just plain annoying. Not only is space really tight on all sides, but the steering shaft runs RIGHT NEXT to the plugs on the left side of the engine. Not convenient at all, unless you are a midget or a small child. The best way is to jack it up, remove the wheel, and attack them from the wheelwell.

After that, you get to have fun changing the cap and rotor on the dizzy that's jammed under the wiper cowl. Fun stuff.

Sevillian273
02-02-11, 02:09 PM
Its not difficult, just the least accessible set of plugs I've ever done. I've never seen a RWD set that was that tight and the only set that Ive found easier to do from underneath the car.

96Fleetwood
02-02-11, 08:07 PM
My Father-in-law has a 1999 Oldsmobile Bravada Platinum Edition that he bought new. It now has 62K original miles on it. What a workhorse!! All it needed was fluid changes, tires, and brakes. The AWD system works well and it has a few luxury options that can't be had in the Blazer. It does lack power and makes horrible gas mileage (especially with the AWD).. but it has never left him stranded and has held up well cosmetically.

hueterm
02-02-11, 08:35 PM
Don't tempt Chad...

I~LUV~Caddys8792
02-02-11, 08:48 PM
We've got a '99 or '00 Bravada on our used car lot at the Nissan/Kia dealer I work nights at, I drove it once. Nice rig, nicer than the '94 Grand Cherokee Limited I drove last month. Felt more car like, more luxurious and rich. Rode softer as well, but lacked the V8 push of the 318 GCL.

I~LUV~Caddys8792
02-02-11, 08:52 PM
To compare the 3800 and the 4.3 in terms of power is a little silly. While the max numbers are similar, the powerbands are completely different.

No Drew, there's nothing silly about that question. They're both large, OHV cast iron V6's built by General Motors and popularized in the '90s and early '00's. Some of us have to ask questions because we weren't born with the knowledge implanted in our brains.

gdwriter
02-02-11, 08:59 PM
When my Dad first started working as a courier driver in the early 90s, he started with an '88 Ford Aerostar that had one problem after another, to the point where I would ask him "How's the Fixed or Repaired Daily now?" whenever I called. A deer did him a favor and totaled it. He then bought an '89 Astro that already had over 100,000 miles on it, and I think it had over 400,000 miles on it when he finally retired it. No major issues with it other than a sometimes leaky rear main seal. Replaced the Astro with a '91 Sonoma and put a couple 100-grand on it; had to replace the transmission in that truck, but again no major issues with the engine.

It's not a particularly refined engine (although I thought it was fine in the '98 Blazer my parents had) and it's not all that great on gas for a V6, but it's certainly durable.

gdwriter
02-02-11, 09:02 PM
Some of us have to ask questions because we weren't born with the knowledge implanted in our brains.Neither was Drew. He just thinks he was. :lol:

Playdrv4me
02-02-11, 09:07 PM
It's a solid motor, but man it was just completely obliterated by the utterly fantastic 4.2L I6 that was designed for the GMT360 line. A shame that engine essentially died with that platform, leaving us a trio of front drive people movers with a car V6.

I~LUV~Caddys8792
02-02-11, 09:15 PM
Yeah, that 4.2L I-6 was a fantastic engine. Amazing horsepower and torque, great driveability, very solid reliability and good fuel economy. My grandpa, great uncle and godfather all bought '02 Bravadas when they came out and nine years later, they've all still got them. I remember my godfather commenting on how quick it was for a truck, and he's used to Corvettes and the other truck in his stable was a '98 K2500 Sierra with the 454. I think I've said this before, but before it hit the market, GM had to detune it a bit, because it was putting out more power than the 4.8 and 5.3L V8 at the time, and almost as much horsepower as the LS1 in the Camaro! Imagine that, an inline six that's much smaller than your big, bad Camaro's V8, but putting out more horsepower and almost as much torque! Apparently if you install a dual exhaust and an intake on a stock 275-290 hp 4.2L, you'll be putting out more than 315-320hp.

drewsdeville
02-02-11, 10:05 PM
No Drew, there's nothing silly about that question. They're both large, OHV cast iron V6's built by General Motors and popularized in the '90s and early '00's. Some of us have to ask questions because we weren't born with the knowledge implanted in our brains.

Yeesh, sorry if you took that offensively.

Sure they were V6's, but I feel their applications were too different to make for a comparison. One was mainly used in a truck application, the other in passenger cars. That said, they will have different characteristics that make them suitable for each.


Just like it wouldn't be fair to compare a Cummins B diesel used in the pickups to a N engine used in a semi. Sure, they are both 6 cylinders produced by the same manufacturer, but for different applications.

The 3.8 and 4.3 were both good at what they did. Given their applications, the 3800 could never have been substituted for the 4.3 (successfully), just like the 4.3 could never have replaced the 3800. I find a direct comparison to be moot.


Neither was Drew.

Definitely the truth :)

I~LUV~Caddys8792
02-03-11, 02:11 AM
Yeah, the 4.3 definitely feels more truck like. The 3800 is by no means short on low end power. If I'm light on the gas, I won't have to exceed about 2200 rpm in normal driving and I'll be able to keep up with traffic just fine, but the 3800 pales in comparison to the 4.3 in terms of low end torque, even with the supercharger. I remember when I first got the Astro, I thought the 4.3 reminded me a lot of a TBI 4.5 in terms of power band and torque curve. The power they put out is really similar too. I wish that my Astro had a tachometer like the S10s and Blazers did. It would be interesting to see where it keeps the RPMs and where it normally shifts at.

I'd really like to compare it to the Jeep 4.0 I-6 in terms of power and torque output as well. I know the 4.3 made more torque than the 4.0 did, but I think the 4.0's torque curve was much flatter and more accessible. Now I'm curious as to how Mopar's 3.9L V6 (a shortened 318) compares to the 4.3, as well as Ford's 4.0 V6.

Jesda
02-03-11, 06:18 AM
The 4.9's ease of access is definitely not the norm for a FWD V8. I tend to prefer RWD for DIY. The RWD Northstar is still a tight fit, but its a bit easier to work on than the FWD version.

I~LUV~Caddys8792
02-03-11, 09:27 AM
When it comes to ease of accessibility for performing tasks under the hood, the 4.3L V6 is an anomaly in terms of RWD domestic vehicles. Most of them aren't that tight.

drewsdeville
02-03-11, 09:34 AM
I definitely agree to all of the above.

A discussion about the Ford 4.0 would be a LOLfest.

Jesda
02-03-11, 03:21 PM
The 4.3 feels more powerful than Chrysler's 318, at least in my mind when comparing the two examples I've driven: Astro and Grand Cherokee.

Rolex
02-03-11, 03:59 PM
I had a 91' GMC Sonoma single cab 5 speed that I drove through high school and college. It was one of the most reliable trucks I've owned to date. In 8 years the only thing I had to repair was the starter and alternator (had both rebuilt). I gave it to my brother-in-law after BEATING on it for 8 years. I believe the odometer quit working for me around 180k, and my BIL allowed his farm hands to use the truck for another 3 years after that before they ultimately destroyed it.

In my high school days I had a stage II Hypertech chip in it, and had the muffler removed and dummy dual exhaust added. It had a nice sound to it for a V6 with "pipes." Back in that day the full size 5.7 liter 4x2 trucks had the TBI system on them. I could run circles around those trucks in the mid to high end of their power curve, and consistently beat them in the quarter mile by 2-3 car lengths. In 94' GM added multiport injection (MPI) to the S10's 4.3 liter V6 and marketed it as the S10 SS. I raced one of those S10 SS trucks (stock with a slushbox) in the quarter mile in my 91' and beat the guy twice by 5-6 car lengths. :cool2:

Playdrv4me
02-03-11, 05:07 PM
The height of 4.3 awesomeness...

http://www.niot.net/blog-images/02_Feb/barrett-jackson-2009-final-1993-gmc-typhoon.jpg

Though I'm sure if the regular 4.3 was annoying to work on, these must be an absolute nightmare.

drewsdeville
02-03-11, 05:18 PM
Don't forget about it's slightly lighter/faster brother, the Syclone:

http://image.automotive.com/f/features/11808359+pheader/0902gmhtp_01_z+all_wheel_drive_1991_gmc_syclone+fr ont_view.jpg


http://www.youtube.com/watch?v=_vBYFQ4Ozw0&feature=related

Playdrv4me
02-03-11, 07:16 PM
I thought about posting the Syclone but since i've always been an suv fanatic my favorite is still the Typhoon.

V-Eight
02-03-11, 08:29 PM
Don't forget about it's slightly lighter/faster brother, the Syclone:

http://image.automotive.com/f/features/11808359+pheader/0902gmhtp_01_z+all_wheel_drive_1991_gmc_syclone+fr ont_view.jpg


http://www.youtube.com/watch?v=_vBYFQ4Ozw0&feature=related

Love how the camera gets thrown back when he stomps it.

I~LUV~Caddys8792
02-03-11, 11:57 PM
Those Syclone/Typhoons may have had the most rattlebox, archaic interiors, but my god, what a truck/suv! I still think those have got to be the fastest SUVs and trucks that anyone has made. I think they even give the SRT-10 Ram a run for it's money.

My cousin had a 91 Sonoma when he was like 19, 4.3L with the five speed. He said it was really quick for it's day as well.

I drove an '00 Bravada today at work, and being probably 500-600 lbs lighter than my Astro, and with 114k miles as opposed to my 250k miles, it was a lot quicker as well. It really felt like a small V8 in one of those.

ga_etc
02-04-11, 02:37 AM
The Typhoon handled and rode better because of the extra weight over the Syclone. I wouldn't turn down the keys to either one of them though. Even the standard 4.3 in the S10 is a quick little truck. The only problem is getting it to hold traction. I drove a '91 reg. cab, short bed, auto with the 4.3 and it would spin the tires if you even thought about pressing the gas too hard. In contrast though, I drove a friend's '00-ish S10 Xtreme, extended cab, 4.3, 5 speed. It wasn't as bad about lighting up the rear tires, but it was PDQ with that manual trans. I overshot 3rd gear on the upshift and hit 5th by mistake (1st time driving the truck). It worked to my advantage though, because just running enthusiastically in 1st and 2nd had already shot me to 65.

Rolex
02-04-11, 09:21 PM
.....Even the standard 4.3 in the S10 is a quick little truck. The only problem is getting it to hold traction.....


When I was a kid we used to race 4 light poles, which is country for 1/4 mile. I once laid a rubber 3 light poles long in my little 91' Sonoma (with bald tires). Making that little truck hook up could be quite a chore. Traction bars put a stop to the wheel hop, good tires and teathering the clutch to try to hook up was tough. The torquey 4.3 in that light truck made for great burnouts though. And it could bark the tires in 4 gears. :cool2:

I~LUV~Caddys8792
02-04-11, 11:14 PM
Back in the day (late '80s) my uncle (ex Chevy dealer tech) had an '84 S-10 that he put a 350 in and would run a 13 second 1/4 mile. I guess that was a pretty popular setup back then.

Rolex
02-05-11, 12:46 AM
Haha, I got a piece of an old Chevy LUV truck one night that was "pro-stocked." He had tubs, drag slicks and a 350 short block crammed into that old truck. I had heard about the guy for a long time before I ran into him that night in my Sonoma. Needless to say he handed me my arse in the quarter mile.