3.0L Duramax Common Problems

The 5 Most Common 3.0L Duramax Problems

Jake Mayock

Meet Jake

Jake is a founder of 8020 Media and has been creating automotive content online since 2017. He has been the lead writer for Chevy Trucks and has transformed it from the old and outdated site it was into what it is today. Jake creates a ton of GM related content for the 8020 Media YouTube channel and specializes in Duramax and Vortec information but has a wealth of knowledge across all GM cars and engines. Jake believes the L5P is the best diesel on the market today.

The 3.0 Duramax seems like a great engine on paper – it can tow a lot, it produces good power, and gets great fuel economy all while being available in half-ton trucks, competing with the poor fuel economy V8’s. The engine has actually proven a lot more reliable than RAM’s disastrous EcoDiesel and Ford’s already retired mini-Powerstroke but it still has a number of problems to be aware of.

The 3.0 Duramax is prone to fuel injector and injection pump failure, EGR issues, and a few smaller maintenance related problems. We’re going to discuss each of these problems in detail and provide some thoughts on overall reliability.

3.0L Duramax Common Problems

3.0L Duramax Engine Problems

  • Crank start issues
  • Oil pump belt replacement
  • Injector failure
  • Exhaust gas recirculation failure
  • High-Pressure Fuel Pump Failure

If you would rather consume this content via a video, check out our 3.0L Duramax Common Problems video below:

1) Crank Start Issues

The most common problem these engines suffer from is an issue with the starter cranking but the engine failing to start. The cause of this issue is still really unknown and it affects virtually all of the trucks that use this engine. This problem only affects the LM2 and not the LZ0 versions of the engine.

There have been varying presumptions about the cause, and General Motors has released several TSBs. A damaged or warped camshaft position sensor wheel, faulty wiring harness, fuel pump, and actuators were all identified as the possible culprit.

Symptoms of Crank Start Issues

  • Long crank before starting
  • Long-crank and no starts but starts on the second attempt
  • Long-crank and no-start

Replacing the trigger wheel is a strenuous and time-consuming task. It requires the total removal of the cab to access the wheel at the back of the engine, and there is still no guarantee that it would solve the problem.

General Motor has also mentioned that a faulty wiring harness, actuators, or fuel pump could cause extended crank time. Recently, GM suggested that an update or software refresh of the engine’s ECU should help sort the issue, and there has been some positive feedback.

2) Oil Pump Belt Replacement

Although the oil pump belt replacement is part of routine maintenance required down the line, it made our list because it is a somewhat complex procedure and therefore expensive to replace. The engine’s oil pump is run by a wet belt always immersed in oil and it is located on the back side of the engine.

Regardless of the belt’s lengthy life expectancy, it still requires replacement after 150,000 miles, making the engine’s design a drawback. The belt is at the back of the engine, and gaining access to it involves the removal of the transmission. Although swapping the belt once it becomes accessible is pretty straightforward, getting to it takes several hours.

Symptoms of Failed Oil Pump Belt

  • Low oil pressure warning
  • Temperature warning
  • Overheating engine
  • Noisy fuel pump

 3) Injector failure

Like most direct-injection engines, the engine has the injectors at the top of each cylinder and delivers fuel directly into the cylinder. The injector is supplied with pressurized fuel by the high-pressure fuel pump attached to the lower driver side of the engine block. Unlike indirect injection engines, direct-injection engines tend to produce higher amounts of particulate matter because the fuel and air are not uniformly mixed.

Consequently, the direct exposure of the injectors to the combustion process causes carbon to accumulate on the injector nozzle, which affects its effectiveness. Although the injectors could last as long as your vehicle, you may want to consider replacing the injector if you notice the following symptoms:

Symptoms of a Failed Injector

  • Rough idle
  • Lean fuel mixture
  • Reduced fuel efficiency
  • Engine misfire
  • Reduced engine performance
  • Illuminated check engine light
  • Crank but no start

The best way of ensuring your injector longevity is by using fuel additives. Fuel additives perform two main functions — they provide lubricity to protect the fuel injectors from wearing out and prevent deposit buildup on the nozzle by flushing the injectors to get rid of the deposit.

4) EGR Failure

Although the EGR system uses a low-pressure EGR alongside a conventional high-pressure EGR system for overall engine efficiency, the system has been known to experience some issues down the line. Oftentimes, the EGR valve gets clogged up with carbon deposits, or the cooler may crack after repeated recycling of extreme temperatures. Consequently, these components would need repair or replacement.

Symptoms of EGR Failure

  • Rough idle
  • Poor engine performance
  • Increased fuel consumption
  • Increased emission
  • Knocking noise from the engine
  • Illuminated check engine light

While GM claims that the clean-sheet design makes the treatment of the engine exhaust gases more efficient and reliable than the traditional DPF and SCR system, the failure of the EGR is a problem that has plagued diesel engines.

5. High-Pressure Fuel Pump Failure

The demand for reduced exhaust emissions brought about direct fuel injection engines, and high fuel pressure fuel pumps were introduced to counter the engine’s compression pressure. Like all direct injection engines, the 3.0L Duramax engine has a high-pressure fuel pump that delivers pressurized fuel to the injectors for combustion.

However, the pump can only last so long — it has an estimated lifespan of 100,000 miles and depending on the driving habits, it could wear down earlier than expected. Unlike the oil pump belt service or trigger wheel replacement, the high-pressure pump replacement does not require dropping the transmission — it is easily accessible by removing the oil pan.

Symptoms of a Failed High-Pressure Pump

  • Reduced fuel efficiency
  • Delayed start
  • Hesitant acceleration
  • Low fuel pressure
  • Power loss
  • Rough idle

Replacing the high-pressure pump is inevitable. However, you can prolong the pump’s lifespan with good maintenance culture and avoid running on low fuel.

3.0L Duramax Reliability

The crank no start issue is the major problem that has ravaged the 3.0L Duramax. Sometimes, the dealership may have to attempt several possible causes before detecting the problem, meaning your truck may stay longer at the dealership. Besides this issue, the other issues discussed, including oil pump belt replacement, high-pressure fuel pump failure, clogged injectors, and EGR failure, are all problems you will have to deal with as part of your maintenance service.

While the crank no start issue and the service requirement of the oil pump belt after 150,000 miles has brought the engine’s reliability into question, it has performed exceptionally since its release. It has proven itself to be a great workhorse, providing the daily drivers with an excellent alternative and just the right amount of power they need to get through their day-to-day activities. 

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  1. I bought a 2020 gmc 1500 Duramax. The check engine light keep coming on and going off. I cared it to dealership couple times. They couldn’t find anything wrong with. When it had 40 some thousand miles it stayed coming on more and more. And got to where when it came on it wouldn’t go into over drive. Dealership ended up putting new transmission in it

    1. Have a 2022 redesigned sierra crew cab elevation 3.0 duramax .at 1322 mileage threw engine code for P2C7A . Aside that truck runs really good, at dealer in pasadena they made it a horrible experience aside denting and scratching the truck..that dealer added 117 miles and kept it 10 day and from what I saw on ny dash cam the work they did in 10 days was maybe 1 hour and they drove 117 miles in one day. A day later At 1478 i had check engine again for same issue brought it to cerritos gmc and the experience was very pleasant. So far it seems alot some diesel have that emmision issue . Hope they come out with an update to fix that issue. Truck is awesome aside that issue.

  2. I purchased 2020 In January the engine light was on when I got it dealership said it was not a problem took it in several times they put over 500 miles on it I finally got it back at the end of April with the light off it comes on every one e in a while but turn back off issues of oil and gas mileage gets about 20 mpg not 30 very disappointed about Chevy product…….

  3. Glow plugs were an issue during turbo diesel in vertical cast iron block, when engine turn over
    were hard first thing from long cool down periods. Gas engines combust fuel, diesel compress.
    Could COLD block temperature be another reason LM2 diesel are so hard to start?
    Glow plugs warm diesel to 488 degrees, unlike Spark plugs to 108 degrees in gasoline.

      1. I’ve never seen one without one but my experience with all diesels I’ve driven or worked on, they all had a glow plug light that came on when you turned the ignition on until right before the engine cranks. You leave the ignition on in this position until the light has gone off then turn the engine over to crank it.

    1. Bought a 22 gmc 3.0 diesel any start up under 40 degrees will shake and rough idle for a minute then smooth out and operate fine

  4. I bought a 2020 1500 sierra 3.0l Turbo diesel. Fuel Economy and power is second to none. Just amazing. But Check engine light came on at 200 km lol. The truck has been to the dealership about 25 times in just 2 years
    (no exaggeration).
    I don’t tow with it or do anything heavy all, Just light city and highway driving.
    In conclusion, American vehicles, no matter what the brand is, are all pile of problems. Toyota NEVER fails.
    I’m trading mine for a Tundra. In vehicles the most important thing is their reliability everything else is gimmicks.

  5. I bought a 2021 Chevy 1500 Silverado with a 3.0 l Duramax. I have just under 19,000 miles and last Thursday 20 Oct 2022 I had a message come across my dash saying there is water in the fuel. I took it to the dealership the next day and they show me a sample of the fuel they drained out of the fuel tank, and it had what looked like oil in the bottom of the glass they took the sample with. Now the dealership is telling me that it was vandalism cause they could not make out what the substance is.
    Am I crazy to think that this should be covered under warranty? Asking for a friend.

    1. Brian – sounds like a warranty issue to me…vandalism seems like an aggressive thing for them to point to. That would require someone to intentionally open your gas tank and pour something into it…

    2. The dealership is saying “vandalism” because most insurance companies will cover the fuel system replacement if claimed under vandalism. The dealership just doesn’t want to pay.

  6. I bought a 2021 Silverado Duramax 3.0l it has 12k miles on it. it has been at the shop for over a month now, had it towed in for a lifter failure, they replaced it and now the second one has failed. at this point I would like a buyback, but the dealership is saying that that’s between GMC and me. Curious if anyone else has had this issue?

    1. Hi Katie,

      I am having the same issue and I is 2022 Duramax. the engine light on around 3500 miles.
      They changed the fuel pump and fuel modular. The light keeps showing up constantly.
      Still at the dealer workshop. Not sure what to do.
      Pls advise if you have any updates on yours.

      1. 2021 3.0L GMC AT4 just started overheating at 50k miles no warning or symptoms just a check engine light and the twmp gauge climbs

    2. Mine is currently @ dealer for lifters. 60 k miles 2020 AT4. They have had it for a week. Did a tear down. Metal in pan & oil. They are recomending motor replacement to GM. We shall see. Maybe they will put a new LZO motor in it.

  7. Sierra duramax 3.0 L 2020. I have a light that comes on occasionally. I use my truck without a load from November to April .. on my first annual trip with a load (camper) There is a light that comes on .. oil pressure ok .. temperature ok .. I continue to drive but before stopping I leave the engine running for 1 minute …. 2 stops and the light is not there anymore .. so I think the detector is somewhere too similar or you have to let the exase line purify itself. No other problem 48,000 km

  8. I have a 2021 gmc Sierra 1500 with the 3.0 diesel. The P2C7A code has come up 8 times since I bought the truck. 6 times since June. It’s been in the shop for the 5th time to day 4 times for p2 code and once for a bad oil sensor 28 days in the shop as of now. Told GMC I want it fixed right or bought back. Most expensive vehicle I have ever bought and so far the most headaches.

  9. Bought 2022 Silverado w/3.0 Duramax in June. Everything has been great till today. Just turned 4K miles. Started up, let it warm up and drove 100ft and it shut down. Message on dash said shift to neutral and start again. Drove another 100ft and shut down again. Happened 4 times. After the 4th time, new message said Engine is in reduced power mode. Luckily I made it to a gas station. Next I see ESC on dash. Then I get a text from Onstar and it says Service Engine and Transmission within 1 day. I checked the def and it’s at 1/2 full and fuel is also at 1/2 full. Called dealer and they sent a flatbed to pick it up. Walked home since I only made it 1/4 mile. What a bummer. No truck and no rentals/loaner available. Merry Christmas!

    1. Realistically I wouldn’t buy any half-ton diesel but that’s just me personally, for me it’s the 6.6L or probably stick with the gasser. If you aren’t towing heavy the new 2.7L Turbo could be a good choice. If I were to buy one it would be a 2023 with the LZ0 engine.

      Diesel fuel is also still a solid $2 more expensive than low-grade so do the mileage benefits really help?

    2. Hell no – I’ve been sitting in a gas station for 1.5 hours trying to make it home FROM the dealershiip. Terrible extended crank issue. Going to sell it if I can get it started – 2021 Tahoe

    3. I own a ‘21 sierra 1500 3.0. It had the intermittent no start issue. It was resolved early and wasn’t that big of a deal really. The mpg is at least 25% better than a 5.3. Right now diesel is $.20 cheaper than gas. The oil change is slightly more, but is a 7500 mile interval so that’s almost a wash. You do have to put DEF in it, which isn’t really that much. Fuel filter change every 25k miles. Pretty easy to do and costs about $20. It’s rated for 9300 lbs towing, I’ve towed over 10k pounds and it did it, but the truck definitely felt it. If you put a lot of miles on a truck and mpg is your goal and you don’t mind doing a little maintenance then a small format diesel is a good choice

  10. I bought a 2020 GMC Sierra 3.0 Liter Turbo Diesel back in late November, and I’ve had it back to the dealer multiple times in less than 3 months. I really like the truck and wanted this specific engine because I have a relatively short commute (20 mins) but also wanted to the towing capability for towing a travel trailer camper. The power is there but I’ve had several issues in the 2 1/2 months since I’ve owned it. The truck has just over 60,000 miles on it but is under a Lifetime Powertrain Warranty. The first issue I had (3 weeks after I bought it) was a P2635 code pop up, Fuel Pump Flow Performance. Dealer looked at it and said nothing was wrong with it after they tested the fuel and all, and told me to put in some diesel fuel additive. Check engine light stayed off until about another 3 weeks later. I stalled out at a stop sign…no power at all…had to get it towed back home (long story short…it was a nightmare). Anyway, dealer towed it back up by them and found that the ground straps melted through. They still don’t know what caused it but they fixed that issue. 3 days after I picked my truck up the check engine light came on again!! The same code P2635, Fuel Pump Flow Performance, popped up again. The truck seems to run fine, however, I have noticed a dip in MPG recently. Anyone have any suggestions? Bad fuel pump? Fuel Pump Relay? ECM? Need some help here, thanks.

  11. I have a 2020 silverado 3.0L Duramax! and at 110k miles I had to change the transmission for a new one! and now it has 120 k and I have the engine light and the timing chain needs to be replaced! In conclusion, the GM is disgusting as a brand! my recommendation was -100

  12. Have had 3- 6.6 2500 before my current 2020 3.0 1500. By far the best truck for mpg out of a diesel. Average 26 with daily driving, not in the city. Have 40k on it now with out a single problem. Wanted to give some positive feedback about a so far really great truck. Have a few friends that have also bought 3.0’s since I’ve owned mine, and also no problems.

  13. 2021 AT4 3.0L LM2. S&B cold air intake and Pulsar Throttle control. Happy to report 0 issues so far. Truck has 42k miles on it. Avg north of 27mpg. People tend to only post problems that may scare people away form these trucks. Hope this helps someone.

  14. I guess I am in the minority. I have a 2021 GMC with the 3.0 and currently have 64K on the odometer. I did have a long start issue right after I got it but they performed the ECM update and I have not had an issue since. The truck gets fantastic fuel mileage during both city and highway driving. I am on the road quite a bit so, as you can see by the miles, I have a lot of extended trips. I do have a flat deck car trailer I haul occasionally and the truck has plenty of power and will easily pull any load you should be pulling with a half ton. Honestly unless I start having issues I plan to buy this engine platform as long as its offered.

    1. Oh yes, 48600 miles on my 2021. I had the long start early too. I tow my pontoon boat in the summer. Tows better than all my 5.3 gas did and still gets 17 MPG towing. Strong 28 MPG all the time not towing.
      I get 700 mile range all the time on a tank.

  15. I want to reply to Brian Cotton:
    I had exact same issue, except mine shut down, would not start and had to be towed to dealer.
    After several weeks, dealer claimed had a fuel problem and they do not warranty a fuel problem. Finally went to insuance and they had the fuel tested and supposedly found the fuel had sugar in it. I did not argue as i wanted them to cover the engine under vandalism, but if you know diesel fuel you know that sugar will not mix with diesel. Sugar goes to the bottom of the tank and does not dissolve; therefore cannot be a problem . I have wished I had got the fuel tested on my own, but did not.
    Supposedly what happened was:
    The sugar froze up the Fuel Pump
    When the Fuel Pump froze up the timing chain broke
    When the timing chain broke the lifters hit the head and bent
    After nearly 3 months, I finally got my pickup back with less than 10,000 miles on it and had an new fuel pump and new engine.
    I certainly feel this should have been covered under the GMC warranty and not insurance that cost me $1,000.00 deductible.
    I will never ever deal with Frank Brown GMC in Lubbock, Texas again and will be sure to tell everyone my sad story.

  16. I had the same issue with my Duramax. I replaced the fuel pump and filter and it still wouldn’t start. I think it was the fuel rail.

  17. Great! I was about to buy a diesel 3.0, now no mas! When GM will go back to tradition, making solid trucks? I think Obama put a curse on GM. and Joe Biden reinforce it.

  18. I have a 2021 high Country with the Duromax 3.0. It is an excellent truck and engine. Long start when new which was fixed with the upgrade to the program. I will buy another.

  19. Love my 2021 Chev with the 3 liter Diesel. As long as I step on the brake before the start button, the engine starts everytime. With 43k miles no problems and no codes. Pulls my 6,000 lb rv like its not even there. Saved $700 the first 3 months on fuel over my 6.2 liter yukon. I average 32 mpg at 70 mph. The best was 34.7 over a 605 mile from SanAntonio Tx to Joplin Mo.

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