What’s the consensus on the Duramax reliability?

[optimusprime]

My 08 is going TU. Time to upgrade. My buddy told me to check out the 3.0 in the Burbs. I haven’t spent too long looking yet so I figured I’d ask everyone here what they thought of them. How’s the reliability and what are the common issues? There’s a nice 22’ RST around my area so it’s an option.

 

[PPK_]

i would not. i have a '25 SLT 1500... pulled a 5000 lb last trailer year... and now the engine is pretty noisy.... also.. if you tow anything... it gets no more mileage than a 5.3 and uses lots of DEF. also the "regen" function is about 10 minutes every hour. not any good mileage during that period either.

i have had lots of oil burners... gas and diesel used to be about even in price... now gas is a lot cheaper. DEF is $18 bucks for 3 gallons.

i am going to under my 3.0 and look at the inspection plate under the bellhousing see if the crank has motion.. they are losing thrust bearings.. in '25 and '26.

 

[JayceeP]

I have a ‘24 XL SLT diesel (LM2). This thing refuses to get much worse than 20mpg on any tank I’ve filled up and easily gets 24+ on road trips. It’s also nice to see 600mi range on road trips too. It’s a highway torque machine and I’m not light on the pedal.

I know early LM2’s had coolant control valve issues and apparently an early swath of the LZ0’s had thrust bearing issues in the Yukon/Tahoe but reports are that this issue has been fixed.

 

[Stbentoak]

i would not. i have a '25 SLT 1500... pulled a 5000 lb last trailer year... and now the engine is pretty noisy.... also.. if you tow anything... it gets no more mileage than a 5.3 and uses lots of DEF. also the "regen" function is about 10 minutes every hour. not any good mileage during that period either.

i have had lots of oil burners... gas and diesel used to be about even in price... now gas is a lot cheaper. DEF is $18 bucks for 3 gallons.

i am going to under my 3.0 and look at the inspection plate under the bellhousing see if the crank has motion.. they are losing thrust bearings.. in '25 and '26.

Misinformed......

No noisier than any of the other engines. Way cheaper on fuel than a 6.2 that uses premium. Gets 40% better mileage. I've owned two of them and both of them have been solid performers. Also, you can buy a 2.5 of DEF at Walmart for less than $9. Uses one container about every oil change... Based on all the travails that the V eights have went through. This is the only engine I would own in this format.

 

[Padraig]

I have a 23 Suburban with the 3.0. about 40,000 flawless miles. On a trip I normally get at least 28/29 mpg. If I drive the speed limit it is around 30 mpg. Hauling a 6,000 # boat I get 18/19. Which is what my old Yukon XL got empty I would definitely get the diesel again. Regen and DEF is not a big deal. It does go through more when towing but still not a deal breaker.

Padraig

 

[PPK_]

Misinformed......

No noisier than any of the other engines. Way cheaper on fuel than a 6.2 that uses premium. Gets 40% better mileage. I've owned two of them and both of them have been solid performers. Also, you can buy a 2.5 of DEF at Walmart for less than $9. Uses one container about every oil change... Based on all the travails that the V eights have went through. This is the only engine I would own in this format.

i may be misinformed. On a road trip with the trailer... 550 miles... 8 gallons of DEF. that is what it used. No guessing. 8 gallons up and 8 gallons back. BLU-DEF is the DEF i use. This is a more expensive brand... i agree. it is $16 or so at walmart. taxes ups that a bit. 9 miles per gallon. Actual....

It also used oil when towing. But is very thin oil... so that is tolerable.

All diesels are noisy.. to really noisy. Some people like the racket.. i don't.

i got the 3.0 due to the problems with the 6.2... i also have a 5.3 in my '24 yukon. i got the 3.0 - even though it has a turbo on it. This turbo is a ball bearing unit.. unlike all the fords and gm gas engines which are sleeves.

if you do not tow... the 3.0 is probably ok.

i will look at my crankshaft clearance later today. i think the motor is noisy... i have rebuilt a few engines... gas and diesel... i do not drive the truck that much.. it might be my imagination. however... it will not take too long to see if the crank has more than i think it is 10thousands of clearance.

i really think the best motors are the gassers.. 6.6 and 7.3. no direct injection.. no AFM.. anyway. hopefully the fella asking his question gets enough feedback to do what he wants.

Pete

 

[JayceeP]

Misinformed......

No noisier than any of the other engines. Way cheaper on fuel than a 6.2 that uses premium. Gets 40% better mileage. I've owned two of them and both of them have been solid performers. Also, you can buy a 2.5 of DEF at Walmart for less than $9. Uses one container about every oil change... Based on all the travails that the V eights have went through. This is the only engine I would own in this format.

Only tricky thing is diesel tends to be more expensive where I am. Currently diesel is 27% more than premium and I would say usually it’s about 20% more. There have been times where prices are the same and/or they flip.

So for me the savings gap actually narrows. I figure it’s around $50/month based on ~10,000 miles of annual driving. Certainly not massive for me but I do love the range of diesel.

 

[Stbentoak]

Diesel is 3.49 where we are. Premium is 3.95 to 4.15. I also like the range. I can go two weeks on a tank of fuel easily. If I can get past this thrust bearing issue I Will be as happy or happier with this one as I was with my 21. So far, it has run pretty Flawlessly on the LZ0.

 

[PPK_]

My 08 is going TU. Time to upgrade. My buddy told me to check out the 3.0 in the Burbs. I haven’t spent too long looking yet so I figured I’d ask everyone here what they thought of them. How’s the reliability and what are the common issues? There’s a nice 22’ RST around my area so it’s an option.

I did look at my crankshaft end play… i guess it is twice what it ought to be… on the other hand… motor shows no signs of distress.. below is drain oil from today… there is more on the magnet than my 5.3 does with a 4k oil change. But.. this engine has seven mains, bigger journals, i think 24 tappets instead of 16 like the eight has. I also opened the filter and did not see much. One thing i don’t like is the filter is probably half the size of the V8 filter. And the 0w20 is thin…

Nothing bad at 11k miles.

 

[JayceeP]

Diesel is 3.49 where we are. Premium is 3.95 to 4.15. I also like the range. I can go two weeks on a tank of fuel easily. If I can get past this thrust bearing issue I Will be as happy or happier with this one as I was with my 21. So far, it has run pretty Flawlessly on the LZ0.

Much more compelling savings for you.

 

[B-train]

I asked my friend who is a 30+ year master GM mechanic about these motors. Mind you, he's the top tech in a busy shop that does ALL the hard, heavy, everything engine, diesel, and transmission work......

"The fuel economy is awesome and they are nice trucks.....if you're not the person who has to pay to fix or maintain them when it comes due. 18 hours shop labor to replace the oil pump belt at 150k. If/when the timing chains (yes, plural) go bad, it's a 50 hour shop rate job to do. It's cheaper at that point to put a new motor in it." His words, and I consider him my GM guru. He knows more about anything GM than anyone I've ever met, or worked with.

Take it for what it's worth.

He just bought a 212k mile 2021, 3500HD that was taken in on a trade. He did all the service on it since day 1 for the owner. Gets 16-17 mpg on the highway, 12.5 around town. No CAFE garbage, 6 speed transmission, doesn't burn oil, and the oil change costs the same as any LT motor. He's also not a fan of the new 10 speeds, hence picking up the high mileage 6 speed truck.

 

[JayceeP]

I asked my friend who is a 30+ year master GM mechanic about these motors. Mind you, he's the top tech in a busy shop that does ALL the hard, heavy, everything engine, diesel, and transmission work......

"The fuel economy is awesome and they are nice trucks.....if you're not the person who has to pay to fix or maintain them when it comes due. 18 hours shop labor to replace the oil pump belt at 150k. If/when the timing chains (yes, plural) go bad, it's a 50 hour shop rate job to do. It's cheaper at that point to put a new motor in it." His words, and I consider him my GM guru. He knows more about anything GM than anyone I've ever met, or worked with.

Take it for what it's worth.

He just bought a 212k mile 2021, 3500HD that was taken in on a trade. He did all the service on it since day 1 for the owner. Gets 16-17 mpg on the highway, 12.5 around town. No CAFE garbage, 6 speed transmission, doesn't burn oil, and the oil change costs the same as any LT motor. He's also not a fan of the new 10 speeds, hence picking up the high mileage 6 speed truck.

I keep seeing this about the oil pump belt but the owner’s manual says it’s actually 200,000 miles/320,000km or every 15 years. Not saying it’s a nothing burger but that’s also a long time for a vehicle to even survive lol.

Every 320 000 km (200,000 mi)
• Replace timing/oil pump belt. Or every 15 years, whichever comes first.

 

[Stbentoak]

I keep seeing this about the oil pump belt but the owner’s manual says it’s actually 200,000 miles/320,000km or every 15 years. Not saying it’s a nothing burger but that’s also a long time for a vehicle to even survive lol.

Every 320 000 km (200,000 mi)
• Replace timing/oil pump belt. Or every 15 years, whichever comes first.

Yep, somebody early on brainwashed two thirds of society about this oil belt. The vast majority of owners of these vehicles won't keep them past, say, 120K miles. Most anything that goes wrong with them internally is covered up until 100,000 miles or six years. By that time, I'm ready to move on to something else.
Every engine has potential issues after they age past 150K miles. This vehicle has a decent powertrain warranty. It's enough to keep me happy through the time I own it.

 

[JayceeP]

Yep, somebody early on brainwashed two thirds of society about this oil belt. The vast majority of owners of these vehicles won't keep them past, say, 120K miles. Most anything that goes wrong with them internally is covered up until 100,000 miles or six years. By that time, I'm ready to move on to something else.
Every engine has potential issues after they age past 150K miles. This vehicle has a decent powertrain warranty. It's enough to keep me happy through the time I own it.

How you liking that Sterling Metallic? I’m
Ordering a diesel Denali XL reserve w/ premium capability pkg. 99% certain I’m going Sterling. High volume dealer but doesn’t have allocation yet so I have a bit of time to decide lol.

 

[Stbentoak]

How you liking that Sterling Metallic? I’m
Ordering a diesel Denali XL reserve w/ premium capability pkg. 99% certain I’m going Sterling. High volume dealer but doesn’t have allocation yet so I have a bit of time to decide lol.

Well, I liked it well enough that I bought two in a row. It's really about the sharpest color {in my mind..}, especially if you black it out. The only other one that I would consider is white. But it just shows dirt so badly that I would be driving myself crazy trying to keep it clean.

 

[TiGrayMSM]

Yep, somebody early on brainwashed two thirds of society about this oil belt. The vast majority of owners of these vehicles won't keep them past, say, 120K miles. Most anything that goes wrong with them internally is covered up until 100,000 miles or six years. By that time, I'm ready to move on to something else.
Every engine has potential issues after they age past 150K miles. This vehicle has a decent powertrain warranty. It's enough to keep me happy through the time I own it.

Just FYI, as I have seen you make this comment previously. The powertrain warranty is 5yr/100k. I wish it was 6, haha!

 

[Stbentoak]

Just FYI, as I have seen you make this comment previously. The powertrain warranty is 5yr/100k. I wish it was 6, haha!

Yes sorry, that was my mistake. I better hurry up and put more miles on it !

 

[dukecharmary]

25 Yukon Duramax, absolutely love it. Nearly 600 mile range on a tank, only uses 1 bottle of DEF per oil change.(My 6.6 loves that stuff). My dealer gives lifetime powertrain warranty with sale, have to maintain perfect records for that though. I'm good to go getting 25 to 29 mpg consistantly.

 

[CTown Duramax]

I love my 2021 LM2 now at 4yrs/46k miles. It runs smoothly, accelerates hard, never gets out of breath and the fuel milage is stellar. The engine develops 460lb/ft at 1,500 rpm. The very early engines like mine needed engine coolant control valve replacement and reinstallation of the main seal. There were prompt service bulletins on these issues and my dealer got ahead of any break downs, gave me a loaner too. According to a dealer/importer friend who does big business in this vehicle, of all the engines available for the big GM SUV, this has been the most reliable.

 

[ducfan]

My 08 is going TU. Time to upgrade. My buddy told me to check out the 3.0 in the Burbs. I haven’t spent too long looking yet so I figured I’d ask everyone here what they thought of them. How’s the reliability and what are the common issues? There’s a nice 22’ RST around my area so it’s an option.

2600 miles on mine so far. Lifetime 22mpg, including break-in and a 500 mile trip towing a trailer (2200 lbs half way, 6200 lbs the other half). Worst tank was 19, and best was 25. I also had the thrust bearing checked according to the TSB, and it was within spec. My build date was 9/25. Except for the middle row captains chairs, I would buy it again.