How is your 4.3L EcoTec3 V6 Engine working out for ya?

Knightfall · July 12, 2016

Always been a fan of the 4.3 since we've had them in S-10 trucks and Blazers (I know the motors aren't similar but still). Now I just want to see a re-envisiominf of the Big-Block V6's from the old GMC trucks. Maybe turbo'd as a base model 3/4 ton motor....

cnrtool · July 13, 2016

I have 47,000 on my 2014. I am happy with it, and as a bonus I am getting a 18.9 average mpg since I bought it. Prior to that, I had a very fun to drive 2003 SS, but it couldn't pass a gas station without gulping 50 bucks worth.

BoomBoom19 · July 13, 2016

I own a 2014 with 22k miles. Honestly couldn't be happier. I had a 2013 prior to this with the v8 and I really cant tell much of a difference. I towed a uhaul (6x12) loaded up to the max from Wisconsin to New York and other than averaging 13-14 mpg, it handled the weight really well and had power to pass when needed. I went for the v6 because i rarely tow, and mainly like a truck because I could throw whatever I want in the back and I sit up above traffic. Plus I feel more safe. Didnt ever feel the need to have the v8 plus I got an amazing deal on my truck.

Baldy_81 · August 7, 2016

I drive a 2014 DC with the 4.3 and Z71 Package. Absolutely love the truck. I modified the Airriad MIT for the 5.3 to fit the 4.3 engine. Currently planning on doing a black bear tune as well. I don't really tow anything, but i have had 1200 lbs of Concrete in the back a few months back, and truck drove like there was nothing there. I would recommend this engine to anyone.

Just curious how much modification was required for the MIT to fit and wether it made a difference or not.

obrien19 · August 7, 2016

Not much modification. Just need a 4 inch to 3 inch coupler for the throttle body and a half inch PVC plug. Hard to say how much of a difference it made. I feel like it did, but others on here would argue that it won't make a difference

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Tw1tch · September 22, 2016

Other than the trans fluid temp running higher than I'm comfortable with, my 2015 4.3L is doing fine. Little over 3000 miles. I'm going to add a Tru Cool Mini Max trans cooler to it very soon & be done with the high fluid temps.

How did that TruCool work for you? Mine still hasn't jumped over 195F, but to be honest I'm a little sketched out by such a high reading on the highway.

Imcrazy · September 22, 2016

I used to have the 4.3 ECO TEC, with 13k miles on my new 5.3 ECO TEC, I'd pay the $800 all day long to get the bigger motor. The 4.3 does the job but, it's nice to have that little extra in the V8. FWIW I had the 4.3 truck for about 30k miles and only a few times did I want more power, mostly on the highway, both trucks are 4x4 3.42 rear end double cabs. If you find a screaming deal on 4.3 don't hesitate they're good motors and I would buy a truck with one again IF it was about 2k less than a comparable 5.3L truck but, new, your talking less than 1000. Also I get the same MPG with this truck as I did the V6. 19 mpg without a trailer hooked up.

11bDad · September 22, 2016

How did that TruCool work for you? Mine still hasn't jumped over 195F, but to be honest I'm a little sketched out by such a high reading on the highway.

Installed it in Dec, but it didn't do much because of the Thermal Bypass Valve they have used since 2014. Install was fairly easy and I was real pleased with the way it turned out. I modified the valve (easy & free), and it really cooled it down. I can run the interstate in 95 degree SC weather at 145 degrees, or sit in heavy traffic at 175. I used the Tru Cool Mini Max 20k btu cooler. Well made. Torque converter and pump went out at 10k miles, so after dealing with that ordeal I feel better about the tranny running cooler.

Baldy_81 · September 23, 2016

I have nearly 80000 kms on my 4.3 and so far my only complaint was towing a 4000 lbs camper with some stuff in the back of the truck. The issue was not being able to keep it in 6th gear so I had to run at 105 km/h @ 2800 rpm in 5th. Would like to know how the 5.3 would fare with that extra HP. Other than its been good.

newdude · September 23, 2016

I've driven one for 300 miles (double cab 4x4) so no ownership experience...but I do have a relevant question for you 4.3 owners. Anyone run the Range AFM delete on theirs? Interested to see some mileage differences between leaving it active and disabled.

I have nearly 80000 kms on my 4.3 and so far my only complaint was towing a 4000 lbs camper with some stuff in the back of the truck. The issue was not being able to keep it in 6th gear so I had to run at 105 km/h @ 2800 rpm in 5th. Would like to know how the 5.3 would fare with that extra HP. Other than its been good.

5.3 would run in 5th with tow/haul on with that load.

NYSierra4 · October 10, 2016

Has anyone done anything with the exhaust? I know most 5.3 owners just say to get a 5.3 but I'd like a little more throat when I hit it on the highway. Thx

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tmo · October 10, 2016

I wanna know how everyone is getting 20+ mpg with their trucks. I have the 4.3 and the closest I've ever gotten to that is 18 when babying it. Normally I get around 15-16 highway.

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NYSierra4 · October 11, 2016

I wanna know how everyone is getting 20+ mpg with their trucks. I have the 4.3 and the closest I've ever gotten to that is 18 when babying it. Normally I get around 15-16 highway.

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So there is a big difference between what the computer tells you and what your actual mpg is. I was averaging around 20-22 with a max of 25 b4 my lift and tires but when I plugged the numbers into a mpg app it was more like 18. After my lift and tires I'm getting around 14-16.

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Edited October 11, 2016 by NYSierra4

azsundevil · October 11, 2016

I wanna know how everyone is getting 20+ mpg with their trucks. I have the 4.3 and the closest I've ever gotten to that is 18 when babying it. Normally I get around 15-16 highway.

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Yep, that's spot-on for me with my 4.3L. I think a lot of people who brag about high MPG are being a little dishonest with themselves and maybe not telling the whole story. When I calculate my MPG by hand, I usually get around 18 if I've been driving economically, and I've seen as low as 14-15 if I've been driving REALLY aggressively (I live in Socal, our freeways are a free-for-all deathmatch).

So there is a big difference between what the computer tells you and what your actual mpg is. I was averaging around 20-22 with a max of 25 b4 my lift and tires but when I plugged the numbers into a mpg app it was more like 18. After my lift and tires I'm getting around 14-16.

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Yeah same here, the computer is waaay off on mine. And I'm running stock tires with no lift. Computer is off by as much as 3-4 mpg sometimes.

GMC2015 · October 11, 2016

I wanna know how everyone is getting 20+ mpg with their trucks. I have the 4.3 and the closest I've ever gotten to that is 18 when babying it. Normally I get around 15-16 highway.

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It boils down to how you drive and what type of truck you drive. Heavier tires and a level will decrease you mileage quite a bit when you have a v6. What did you average when the truck was stock?

This is what I've averaged so far with mine. 70% highway driving and 30% stop and go city driving. Also mixed with some spirited driving (Single cab, 2WD, 3.23s, bone stock)