Duramax 3.0 millage (@51k miles now)

SC4R3C120W · February 17, 2022

Just bragging a little. My trip meter tends to lie in my favor by roughly 1mpg, but i haven't reset my 2nd trip ever. Took this shot before going to the dealer a few months ago in fear that they may unplug the battery and reset it.

A little about my truck. I commute 60 miles, one way, to work and it takes 45 min. The 60 mile drive home takes me 2 hours, so it does see both stop&go and cruising speeds. Without bad traffic, i tend to get 32mpg, but trip usually shows 30-31. Right now i have 265/65/18 on it, but plan on going to 275/70/18 when they wear out. These michelins are great and with 51k on them now, they still look new.

Edited February 17, 2022 by SC4R3C120W

SC4R3C120W · February 17, 2022

These shots were from my camping trip with the family. Had two adults, a child, and all my camping gear (see camping/overland thread for a pic or two) going up and down mountains around 80mph. Drove from southern california amd stopped in salt lale city utah, drove up to glacier park montana, down to yellowstone and grand tetons (wyoming), then to Estes park (colorado), then back home. Did over 4k miles, took pics at all pumps and saved receipts, and trip showed 26 on average. Actually doing the math, i ended up with 28.8

Edited February 17, 2022 by SC4R3C120W

It's Tim · February 17, 2022

My commute is 7 minutes one way, I don't worry about how much fuel is consumed, my time is worth a lot more.

swathdiver · February 17, 2022

18 minutes ago, It's Tim said:

My commute is 7 minutes one way, I don't worry about how much fuel is consumed, my time is worth a lot more.

For your motor's sake, take the long way home to burn off the condensation in your crankcase.

Keith A Thompson · February 17, 2022

Added a k&n air filter and got 32.4 MPG after 70 miles (pure highway)

SC4R3C120W · February 17, 2022

I'd like to add the S&B CAI, but not possible at the moment living in California. Waiting for CARB status, if ever.... and i know that CAI mostly don't do anything, but if there's a chance to increase mileage at all, it'll be worth it for my long commutes.

Dirk13 · February 18, 2022

I do 87 miles one way, 2 or 3 times a week.

My Silverado with 3.0 has averaged 24 mpg over its 26000 mile life. My drive is all highway so I’m doing 70-75 and 24 is the result. The times I’ve driven the drive at 60-65 I’ve gotten 27-28.

Keep us posted on how the truck does as the mileage increases. Is your truck 2wd?

dieselfan1 · February 18, 2022

19 hours ago, It's Tim said:

My commute is 7 minutes one way, I don't worry about how much fuel is consumed, my time is worth a lot more.

Who cares Timmy.

Add something useful once in a while.

SC4R3C120W · February 18, 2022

14 hours ago, Dirk13 said:

I do 87 miles one way, 2 or 3 times a week.

My Silverado with 3.0 has averaged 24 mpg over its 26000 mile life. My drive is all highway so I’m doing 70-75 and 24 is the result. The times I’ve driven the drive at 60-65 I’ve gotten 27-28.

Keep us posted on how the truck does as the mileage increases. Is your truck 2wd?

My truck is 2WD. I do have the backseat under storage full, bug out/emergency bag and water, tool box, and the rack system with "roof" rack on it. so I'm not as lean as i could be. Plan on getting 33" tires soon too and wonder how adding 20lbs per wheel will change things (plan on getting KO2's in 275/70/18)

seamus2154 · February 20, 2022

Wow, that is fantastic! I average 24-26 most of the time but its mostly hot hear in Fla., so always AC and the turnpike here is 80 mph and above if you dont want to get run over! LOL Very encouraging! we are driving out west and up to Montana in May, looking forward to it.

I can tell you from my own experience with my old 2500 Duramax 6.6...adding any weight to the tires and rim will significantly change your mileage. I added a little more than 20 lbs but had more power but it lost 3-4 mpg depending on how much city driving as that was the worst, coming off stop lights. 7 months later I went back to stock rims and tires !!

Thanks for posting, good stuff!

How has she held up in 51,000 miles. Warranty, maintenance, issues ???

Thanks

jaslon · February 20, 2022

On 2/17/2022 at 3:35 PM, Keith A Thompson said:

Added a k&n air filter and got 32.4 MPG after 70 miles (pure highway)

Was this just the drop in filter or the whole system setup?

SC4R3C120W · February 22, 2022

On 2/19/2022 at 9:31 PM, seamus2154 said:

Wow, that is fantastic! I average 24-26 most of the time but its mostly hot hear in Fla., so always AC and the turnpike here is 80 mph and above if you dont want to get run over! LOL Very encouraging! we are driving out west and up to Montana in May, looking forward to it.

I can tell you from my own experience with my old 2500 Duramax 6.6...adding any weight to the tires and rim will significantly change your mileage. I added a little more than 20 lbs but had more power but it lost 3-4 mpg depending on how much city driving as that was the worst, coming off stop lights. 7 months later I went back to stock rims and tires !!

Thanks for posting, good stuff!

How has she held up in 51,000 miles. Warranty, maintenance, issues ???

Thanks

51,000 miles and 3 issues:

First two issues occurred on our road trip at 35,000 miles. Had multiple codes: P25A2, U0146, U0100, U0101. Read up about it and could have been not parking on level surface and truck rolling while in park to give speed sensor an error. Errors cleared on their own and dealer did nothing when i went for an oil change. Never came back

Last issue was code P1488 at roughly 49,000 miles. Looked it up and found bulletin describing leak in exhaust pipe and bad sensor. Took to dealer for 50k service (oil change, coolant flush, brake fluid flush, fuel treatment, and car wash :.) ), they replaced the clamp and sensor as mentioned on bulletin and no issues.

Hoping this will be the last issue as i love this truck. I had a 2014 5.3L i traded in because of the potential of a bent rod and other things that was out of warranty.

seamus2154 · February 23, 2022

Thats a great report at 50K. I have had a few 6.6 duramaxes, many LS motors and a couple of the LT motors. They all have issues. Its the big stuff that I am worried about with any car. Catastrophic stuff. I could care less about any small thing on the outside of the motor that can be tended to. They can improve replacment parts as they have with all the previous known issues. But when transmissions and motors have to opened up or have total failures....I'm out! The rear main seal issue was concerning and annoying...but fixable and seems to have been addressed, because most were earlier trucks. Understandable with a new motor to iron things out. But the core of this motor and the package so far are above average for GM.