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2021 Chevy Silverado LT LM2.
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17 Posts
Discussion Starter #1
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!
 

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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!
 

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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????
 

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2021 Chevy Silverado LT LM2.
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17 Posts
Discussion Starter #4
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!
 

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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
 

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2021 Chevy Silverado LT LM2.
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17 Posts
Discussion Starter #8
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
 

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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
 

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2021 Chevy Silverado LT LM2.
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17 Posts
Discussion Starter #10
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
 

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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.
 

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2021 Chevy Silverado LT LM2.
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17 Posts
Discussion Starter #12
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.
 

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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.
 

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2021 Chevy Silverado LT LM2.
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Discussion Starter #14
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
 

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2021 AT4 Duramax
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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.
 
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