[BCBren]

Hey all, I’m new to the site, GM Ownership, and half-ton diesel. I just traded my ‘18 5.0L F150 because, well, it was garbage after 40000 kms!
I purchased my 3.0L Silverado on Dec 4. Threw a sensor code in the emission system on day one. Programming issue. Dealership reprogrammed it and so far so good. Truck rides amazing and gets insane mileage.

I looked and did not see a thread going for 2021 owners so I wanted to start one up to share my experience with other owners and to offer up honest reviews on the performance an longevity of this truck for others considering a 3.0L

if there’s already a discussion going elsewhere on the site that I could not find please send a link!
Thanks all!

 

[doghouse bound]

Hey all, I’m new to the site, GM Ownership, and half-ton diesel. I just traded my ‘18 5.0L F150 because, well, it was garbage after 40000 kms!
I purchased my 3.0L Silverado on Dec 4. Threw a sensor code in the emission system on day one. Programming issue. Dealership reprogrammed it and so far so good. Truck rides amazing and gets insane mileage.

I looked and did not see a thread going for 2021 owners so I wanted to start one up to share my experience with other owners and to offer up honest reviews on the performance an longevity of this truck for others considering a 3.0L

if there’s already a discussion going elsewhere on the site that I could not find please send a link!
Thanks all!

Hey all, I’m new to the site, GM Ownership, and half-ton diesel. I just traded my ‘18 5.0L F150 because, well, it was garbage after 40000 kms!
I purchased my 3.0L Silverado on Dec 4. Threw a sensor code in the emission system on day one. Programming issue. Dealership reprogrammed it and so far so good. Truck rides amazing and gets insane mileage.

I looked and did not see a thread going for 2021 owners so I wanted to start one up to share my experience with other owners and to offer up honest reviews on the performance an longevity of this truck for others considering a 3.0L

if there’s already a discussion going elsewhere on the site that I could not find please send a link!
Thanks all!

 

[doghouse bound]

hey
my son and i just bought 2 same day together .rst silverado.traded in my tundra after rusting out .
no issues as of yet only 85 miles on her. plugging in block heater when in teens how about you????

 

[BCBren]

Congrats on the new trucks! I ended up purchasing an LT. I’ve got about 450km on it now no issues so far it runs like a dream. Uses approx half the fuel that my F150 used.
We have been lucky with our weather so far and haven’t been too cold over night so I haven’t plugged in yet. I’ll start plugging in around -10 or -15 C (manual recommends plugging in if colder than -18 C. Engine will idle around 7-800rpm for around 10 mins before driving away. She gets up to temp within a couple KMs. Loving it so far!

 

[NYS-LM2]

The 3L diesel thread is under LM2 - thats the new engine code.

 

[BCBren]

The 3L diesel thread is under LM2 - thats the new engine code.

Awesome thanks NYS I’ll check it out!

 

[doghouse bound]

fuel mileage?????

i am averaging 22 mpg so far with only 130 miles so far.

what are you guys getting???? i am 50% city and 50% highway driving to work

 

[BCBren]

fuel mileage?????

i am averaging 22 mpg so far with only 130 miles so far.

what are you guys getting???? i am 50% city and 50% highway driving to work

I am averaging 22-24mpg mostly highway so far in small town mountain country

 

[Scotts 3.0 I-6 4x4 2021]

Hey all, I’m new to the site, GM Ownership, and half-ton diesel. I just traded my ‘18 5.0L F150 because, well, it was garbage after 40000 kms!
I purchased my 3.0L Silverado on Dec 4. Threw a sensor code in the emission system on day one. Programming issue. Dealership reprogrammed it and so far so good. Truck rides amazing and gets insane mileage.

I looked and did not see a thread going for 2021 owners so I wanted to start one up to share my experience with other owners and to offer up honest reviews on the performance an longevity of this truck for others considering a 3.0L

if there’s already a discussion going elsewhere on the site that I could not find please send a link!
Thanks all!

2021 Silverado RST 4x4 duramax 3.0 i-5
Greetings...first week under the 500 mile mark got into some mud to which later produced a code of ESC trouble.. conmenced through the next day. Called GM Svc at the same time driving switched from 4x4 to 2wd the back the code went a way as well as allowing my Cruise control to work again.....

Second tank of diesel seems to be using much more... will keep you informed

 

[BCBren]

2021 Silverado RST 4x4 duramax 3.0 i-5
Greetings...first week under the 500 mile mark got into some mud to which later produced a code of ESC trouble.. conmenced through the next day. Called GM Svc at the same time driving switched from 4x4 to 2wd the back the code went a way as well as allowing my Cruise control to work again.....

Second tank of diesel seems to be using much more... will keep you informed

I hope you get it all figured out. So far I have 2000kms and no issues truck is using appropriate amount of DEF. I am in Canada and the weather has been unusually warm this season. Temp dips to around -10 c. So far the truck does not get the best mileage when cold but when I heat up I average around 7 litres / 100 km on the highway and around 10 - 11 in town.
No other issues so far it’s a great truck just worried about my overall useage and how it will affect the dpf and emissions system.
Fingers crossed! It’s still a far better truck than my ‘18 F-150

 

[dbaamco]

I have 1700 miles on my 2021 Denali 3.0 diesel. Went into limp mode and set check engine light. After shutting off, limp mode reset and i was able to make it to GMC dealer. They told me it was a software update. I asked how does it run perfect for 1700 miles, failsafe and it is software. I did not get a good answer. AT 1900 miles now, it runs poorly. Back to battle with dealership.

 

[BCBren]

I have 1700 miles on my 2021 Denali 3.0 diesel. Went into limp mode and set check engine light. After shutting off, limp mode reset and i was able to make it to GMC dealer. They told me it was a software update. I asked how does it run perfect for 1700 miles, failsafe and it is software. I did not get a good answer. AT 1900 miles now, it runs poorly. Back to battle with dealership.

Man that is really too bad. My experience with dealerships has been pretty hit and miss. My truck has thrown a code in the emissions system (Def sensor) and they updated the coding and not one issue since. Decent cold weather performance and even better warm weather performance.
I am finding tho that the gmc dealers in my area do not fully understand this engine yet and it has been frustrating having any kind of diesel-related maintenance done to this truck. Also, seems there are no parts available in Canada and they are having to be ordered.

 

[Eddie A]

I am averaging 22-24mpg mostly highway so far in small town mountain country

Just got mine Thursday(first diesel) I've driven about 250 miles so not very far but I'm hitting 26mpg. I'm being pretty conservative right now though.

 

[BCBren]

Decent! I just completed an 8h round trip and was pulling a 2500 lbs pop up camper. Averaged out to something like 10L/100kms. Not bad. Better mileage than my old 5.0L with no payload lol

 

[Un-Plugged]

Hey All! 2021 AT4 on the road for two months just hit 4,000 miles today. Averaging 24.5 MPGs don’t trust the computer use your calculator and do the math. Computer is always 2 MPG lower than actual.

Been using Hot Shots Secret additive Diesel Winter Anti-Gel during the cold NY February and March. Just switched to the Every Day Diesel. Noticed a big difference once I started using it. I will say use the funnel in the glovebox they give you for the DEF to help you add it to the fuel tank. Push the funnel all the way in the filler neck and hold it in place as there are two flaps you have to open or else it just spills all over the ground and on your brand new paint... don’t ask me how I know.

I plan on going to the local Pilot to fill the DEF tank when I need it. I’m at 46% oil life right now and 1/2 tank of DEF. Have not done any towing yet.

I also did extensive research to find oil for this engine since it’s not on any shelves at Wally World or Auto Zone. I did find it on Amazon as Mobil 1 ESP X2 0W-20. Apparently Mobil manufactures the oil for GM and it was originally designed for German high end sports cars.

As far as issues I had one the day I took delivery on the truck. When I pulled into my driveway the infotainment went into DEMO MODE. I was able to have it reset it by calling OnStar but I have never been able to use the trucks cellular service and features. OnStar explained that I will have to go to the dealership and have them reset it. Well I haven’t had time for that yet. I figure I will do it at the one and only time I have them change my oil with the free first oil change.

 

[aldehaai]

I purchased my 2021 3.0 Duramax back in November of 2020 and have had it at the shop for the check engine light coming on 4-5 times. Im getting pretty agitated by it since they now make you pay the monthly fee for the mychevrolet app which is no good when the check engine light is on. I just dropped my truck off today and told the dealer i am very disgusted with all this check engine light bs. I now have 14,000 miles on the truck and i absolutely love the truck but this check engine light issue takes up alot of my time. Iowa has the lemon law to protect against stuff like this and i am about to pull the trigger on that. Its sad as i have been a very loyal Chevy owner all my life as I purchase a new vehicle every 2 years but this has really soured me. I hope you all are having a better experience with these 3.0 Duramax's than i am.

 

[NYS-LM2]

I purchased my 2021 3.0 Duramax back in November of 2020 and have had it at the shop for the check engine light coming on 4-5 times. Im getting pretty agitated by it since they now make you pay the monthly fee for the mychevrolet app which is no good when the check engine light is on. I just dropped my truck off today and told the dealer i am very disgusted with all this check engine light bs. I now have 14,000 miles on the truck and i absolutely love the truck but this check engine light issue takes up alot of my time. Iowa has the lemon law to protect against stuff like this and i am about to pull the trigger on that. Its sad as i have been a very loyal Chevy owner all my life as I purchase a new vehicle every 2 years but this has really soured me. I hope you all are having a better experience with these 3.0 Duramax's than i am.

I feel your pain but I would say get used to the CEL because they seem to be a regular occurrence on this vehicle. I just can't believe the number of software updates that have been needed. I usually clear them (if possible) and let them store up and take it in once a month. The vehicle platform is in it 2nd yr and i would have thought that the software engineers would have figured out the bugs, but I guess we are the Guinea pigs - helping work out the bugs.

The first problem I had with a dead battery syndrome it took them 34 days (yes 34 day for one visit) to fix it. Basically the dealership I purchased from does not have any competent diesel tech's and their service department is subpar at best, for which them make no excuses. They rarely get things fixed correctly on the first visit. Once the honeymoon period is over and warrantee is up I will find a competent service center.
On the plus side, the truck rides awesome, its the first truck that I have owned since 1974 that my wife actually says "lets take the truck instead of the car". And the fuel mileage is outstanding, but of course they have driven diesel fuel up to almost $4/gal......we can't win.

 

[NYS-LM2]

I forgot to mention - all the problems happened with under 4000 miles on the clock.

 

[dap22]

Couldn't pass this one up. Traded my 2017 GMC Sierra Denali with the 6.2 that I loved,for this beast. Found it at a VW dealer who said the eccentric guy who bought it couldn't fit it in his garage. It had 3860 miles on the clock and I'll be taking it tomorrow on a 2 day trip to visit the wife's family. Thus far it's a great ride. I love the Pacific blue color and of course the diesel.

 

[Mntman1985]

2021 GMC Sierra Elevation Crew with 6.5 bed. This truck is replacing a 2018 Ford F150 3.5 Ecoboost that was a complete POS. So far love the truck, but here in Alaska it will earn my trust as time goes on. I use my truck like a truck, love it so far. The 3.0 is flawless and efficient, no issues to date. Will update as time goes on.