3.0L Duramax regrets

Valgmcsierradiesel · August 23, 2021

On 4/2/2021 at 10:49 AM, Wormydog1724 said:

Anyone else regretting going with the 3.0L Duramax?

In all of my previous GM trucks I’ve had the 4.8, the 5.3, the 6.0, and 6.2 gassers and I thought I would try something different this time, especially since the duramax was reduced in price for ‘21.

After driving it for 5k miles I’m having regrets. Sure the mpg’s are slightly better, nowhere near the advertised mpg’s though, but the overall power to me just isn’t there.
When I go to pass someone at 65mph and put it to the floor, it reminds me of the seriously underpowered 4.8 I had in my 2008 Silverado. Just doggy and laggy and doesn’t seem to have the power to propel it forward quickly. The 4.8 had slightly more hp at 285hp but a disappointing 295lb.-ft torque. I hated everything about that engine.

The duramax eventually gets me there but when I’m having to go around a semi I don’t need to be wasting time while my rubberband winds up. I understand it’s ‘only’ 277hp. I would like it if there was a chip that could get it to 300hp but then I’d be worried about the unintended wear and tear on all of the other components maybe not being able to withstand the added power over the long term.

Looking back I really should have waited and found a 6.2 AT4 in the color I wanted.

I thought the same thing. Until I put a banks power pedal commander on it along with the I dash gauge let me tell you I’m in love with this truck.

Creg · August 24, 2021

Purchased 2020 LT with 3.0 diesel in July 2020. Addressed the oil changes regularly as required.

Up until 3 weeks ago, I'd have said I was pretty happy.

However . . . . . . . .

Changed fuel filter two weeks ago, at 29k miles - noticed oil residue covering skid plate. Took into dealer last week for incremental oil change and they confirmed that a oil leak exists.

Returned to dealer today for a diagnostic evaluation - it's been there all day but no word yet on the issue.

It does strike me odd that at 31k such a matter exists after only 15 months service.

any thoughts or comments . . . . . . . . ?

Lonnie Marco · August 24, 2021

Been great pulling small trailer from south Florida to truckee California pulled great up the biggest hills and kept set speed up or down

37500 MILES ON MY 2020 TRANSMISSION EXPLODED south Florida flat country cruis set at 60 pulling uhaul motorcycle trailer with my road glide felt like I got smashed in the back it was violent and left me stranded for 12 hours I average 26mpg 60mph no trailer ac on

Creg · August 24, 2021

16 hours ago, Creg said:

Purchased 2020 LT with 3.0 diesel in July 2020. Addressed the oil changes regularly as required.

Up until 3 weeks ago, I'd have said I was pretty happy.

However . . . . . . . .

Changed fuel filter two weeks ago, at 29k miles - noticed oil residue covering skid plate. Took into dealer last week for incremental oil change and they confirmed that a oil leak exists.

Returned to dealer today for a diagnostic evaluation - it's been there all day but no word yet on the issue.

It does strike me odd that at 31k such a matter exists after only 15 months service.

any thoughts or comments . . . . . . . . ?

UPDATE - got call from dealer, it is the main seal leaking

required part is currently backordered so no repairs have been done yet

AONYX · August 31, 2021

Had my 21 RST 3.0 for 6 months, just under 6k miles. Love it so far. I have had really no major issues so far. A couple small things...mainly being the infotainment system is glitchy when trying voice to text and with syncing with my samsung galaxy. The only other issue is that after the truck has been sitting in the heat, occasionally the AC won't come on when I start it. I have to turn off the AC and turn it back on once, sometimes twice, before it kicks in, this only happens occasionally. Haven't been back to the dealer since buying it, but I am going to get the oil changed and I'll mention it at that time

For MPGs I am getting typically 20-22 for city driving. I was getting 33 with a tailwind down the VA eastern shore going around 60. More typically its 27-29 on the highway averaging around 26-28 for a 600 mile tank when it is mostly highway, and the manual calculation at the pump usually beats the computer by 1-2 mpgs. I am not a particularly heavy footed driver.

Just towed a 6.5k lb travel trailer this past weekend, and I was averaging 13-14 going 55-62. Had no issues with towing either, felt like I had plenty of truck for the trailer.

Overall, I feel like it has plenty of power, its not as quick a my MINI Cooper S, but quick enough for getting on the highway and passing if needed. No regrets so far.

Rebel30R · August 31, 2021

Looking Green Engineering, they specialize in eco- diesel tuning. A simple one and done reflash. No deleting of any kind.
Ran into them when a Customer came to us from the dodge dealer after they “ performed a recall” and they ended up derating his truck. Customer was furious. They’re replay was that there was nothing that they could do.
That’s when he came to us and we found Green Engineering. Once done it was better than before. Evens my tech was surprised at what it could do.

Tjripper14 · September 23, 2021

On 4/2/2021 at 10:49 AM, Wormydog1724 said:

Anyone else regretting going with the 3.0L Duramax?

In all of my previous GM trucks I’ve had the 4.8, the 5.3, the 6.0, and 6.2 gassers and I thought I would try something different this time, especially since the duramax was reduced in price for ‘21.

After driving it for 5k miles I’m having regrets. Sure the mpg’s are slightly better, nowhere near the advertised mpg’s though, but the overall power to me just isn’t there.
When I go to pass someone at 65mph and put it to the floor, it reminds me of the seriously underpowered 4.8 I had in my 2008 Silverado. Just doggy and laggy and doesn’t seem to have the power to propel it forward quickly. The 4.8 had slightly more hp at 285hp but a disappointing 295lb.-ft torque. I hated everything about that engine.

The duramax eventually gets me there but when I’m having to go around a semi I don’t need to be wasting time while my rubberband winds up. I understand it’s ‘only’ 277hp. I would like it if there was a chip that could get it to 300hp but then I’d be worried about the unintended wear and tear on all of the other components maybe not being able to withstand the added power over the long term.

Looking back I really should have waited and found a 6.2 AT4 in the color I wanted.

You must have got a lemon because my 3liter moves down the road with authority no matter where I'm at in rpm or mph range. The diesels don't build power like gas motors so punching a diesel and expecting a high Rev pull isn't what they do. Look down at your speedo and watch it quickly gain. That torque hits instantly and that's it but it pulls hard still...completely different feel but mine yanks good all the way to rev limiter. My 3l would smoke my 2013 5.3 and laugh at a 4.8L.

Tjripper14 · September 23, 2021

1 minute ago, Tjripper14 said:

You must have got a lemon because my 3liter moves down the road with authority no matter where I'm at in rpm or mph range. The diesels don't build power like gas motors so punching a diesel and expecting a high Rev pull isn't what they do. Look down at your speedo and watch it quickly gain. That torque hits instantly and that's it but it pulls hard still...completely different feel but mine yanks good all the way to rev limiter. My 3l would smoke my 2013 5.3 and laugh at a 4.8L.

To add on MPG’S, my truck has just under 7k and I ran a trip to Green Bay from Detroit and on way out averging about 77mph I was at 28.3 mpg. On trip back I had 2 other drivers and me at the helm, one was a lead foot( 80-85mph) and other was around 80; we had lots of rain and I still average over 26 mpg. Mpg are insane!!! I have got multiple runs over 100 miles over 30mpg while maintaining at least low 70's speeds.

redwngr · September 23, 2021

Mine pulls like a champ too.

14000 miles and lifetime fuel economy over 25.5 usmpg.

I log every fill and track both dic numbers and hand calc numbers.

I ran several 1500 V8 8 spds doing the same job and they got 20.

I'd argue that the 'lemon' has/had an undiagnosed mechanical problem

Turbo actuator mounted loose was one of the documented issues that would have caused similar performance issues.

Lack of performance was one of the possible symptoms

Ad Tj points out above, steady speed runs will give great numbers.

Edited September 23, 2021 by redwngr

T1dan · September 24, 2021

Just traded my 2020 Silverado 5.3 for a 2021 GMC Sierra 3.0 and honestly will never go back to gas. The 3.0 with the 10spd is so smooth and has great power. The range alone is worth it.

OliverDennis52 · September 25, 2021

On 9/23/2021 at 8:38 PM, T1dan said:

Just traded my 2020 Silverado 5.3 for a 2021 GMC Sierra 3.0 and honestly will never go back to gas. The 3.0 with the 10spd is so smooth and has great power. The range alone is worth it.

This - I don't have any such issues passing semis on the highway. You can't simply push the pedal to the floor, it doesn't respond that way. Press, don't jam, the pedal and stay in the power band down low and mine launches right past them. Love every bit of it.

Agriont · September 26, 2021

20 hours ago, OliverDennis52 said:

This - I don't have any such issues passing semis on the highway. You can't simply push the pedal to the floor, it doesn't respond that way. Press, don't jam, the pedal and stay in the power band down low and mine launches right past them. Love every bit of it.

So getting to 75MPH or 120 Kilometres per hour is how quick in comparison to gas? What is your experience towing?

OliverDennis52 · September 29, 2021

I have no idea how it compares to gas, I only have the one truck. Mine gets up to speed quickly (in my mind) and when passing the semis, you just have to plan your moves and know how to get the most out of the powertrain by paying attention and learning how it responds under various conditions. As for towing, I haven't had that opportunity yet but towing season is quickly approaching.

KARNUT · September 29, 2021

With speed limits in Texas at 75 mph on most roads. Many two lane roads. Passing a semi doing 60-65 mph. It’s really easy to hit cut off speed with any new truck if you mat it. I don’t linger passing a semi in any condition, especially two lanes. The cut off is an uneasy feeling while passing. I’ve gotten more patient since retirement. Worries about the cut off was quickly eliminated with a tune with all my past trucks. I imagine most of these trucks are pretty close in passing power. And equal at the cut off. Caution is advised with all.

Dirk13 · September 29, 2021

43 minutes ago, KARNUT said:

With speed limits in Texas at 75 mph on most roads. Many two lane roads. Passing a semi doing 60-65 mph. It’s really easy to hit cut off speed with any new truck if you mat it. I don’t linger passing a semi in any condition, especially two lanes. The cut off is an uneasy feeling while passing. I’ve gotten more patient since retirement. Worries about the cut off was quickly eliminated with a tune with all my past trucks. I imagine most of these trucks are pretty close in passing power. And equal at the cut off. Caution is advised with all.

Speed cut off? Isn’t it like 98 mph? Man you must really not like being beside them if you need to pass them doing almost 100.

No rAgrets on my 3.0 in 13,000 miles