5.3l ecotec3 engine problems
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The 5 Most Common Chevy EcoTec3 5.3L Engine 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 He has been the lead writer for Chevy Trucks and has transformed it from the old and outdated site it was into what it is today.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 Vortec engine family was plagued by problems with oil consumption and AFM, leading to GM developing the new EcoTec3 engine family in 2014.

However, the EcoTec3 engine family, including the 5.3L engine still suffer from AFM related problems. Additionally, the 5.3L engine specifically has common problems with carbon build-up, fuel injector failure, 4WD, fuel level sensors, and lifters caused by AFM.

This guide is going to dig into each of the common problems of the 5.3L EcoTec3 and discuss overall engine reliability.

Engine Variations & Overall Reliability

The 5.3L EcoTec3 engine is a small-block V8 engine, similar to its Vortec 5300 predecessor. The engine was produced in 4 different variations, the L83, L8B, L82, and L84.

  • L83
    • 2014-2019 Chevy Silverado and GMC Sierra
    • 2014-Present Chevy Tahoe and GMC Yukon
    • 2014-Present Chevy Suburban and GMC Yukon XL
  • L8B
    • 2016-2018 Silverado and Sierra 1500
  • L82 & L84
    • 2019+ Silverado and Sierra 1500

These engines are all considered to be reliable. They don’t tend to suffer from any catastrophic problems but they do frequently have issues with lifter failure caused by active fuel management. Additionally, the fuel injectors fail frequently which is another common problem.

The lifter and AFM issue will typically result in problems by the time you reach the 200,000 mile mark – but there are some cases of engines lasting way longer or even way shorter.

Chevy EcoTec3 5.3L Engine Problems

  1. Carbon build-up
  2. Fuel injector failure
  3. 4WD transfer case sensor failure
  4. Fuel level sensor failure
  5. Active fuel management – is it still a problem?

1. Carbon Build-up

One key difference between the Vortec and EcoTec3 engine families is fueling. While the Vortec engines used port-injection the EcoTec3 engines were built with direct fuel injection. With port-injection, gasoline is injected into the intake ports where it then travels to the cylinders which helps clean any gunk out of the intake ports.

On direct injection engines, the fuel is injected directly into the cylinders, completely bypassing the intake ports. Because the intake ports are bypassed, there is no high-pressure fuel flow to keep them clean and gunk free. This results in a build-up of gunk or sludge as a byproduct of oil and fuel burn that lines the intake ports.

Symptoms of Carbon Buildup

  • Rough idling, stuttering at idle
  • Decreased power and shaky acceleration
  • Engine misfires
  • Slightly lean AFR ratios

You will probably start to notice some carbon buildup effects around the 70,000-80,000 mile range. The only true way to fix this is to regularly clean the intake ports by removing the manifold and walnut blasting or pipe cleaning the valves.

2. Fuel Injector Failure

Due to the high heat and extreme pressure, fuel injectors usually wear out over time. They can become gunked up, begin leaking, loose pressure, or simply completely fail. On the 5.3L engine, the injectors are mostly known to completely fail.

When an injector fails, it either fails in an open or a closed position. When an injector fails open it sprays too much gasoline into the engine, and vice versa when it fails closed. On these engines, they commonly fail closed which results in no gasoline entering the cylinder with the failed injector.

Each cylinder has its own injector, but they do at least tend to fail one at a time, rather than all at once. Bad injectors will certainly limit the driveability of your car and will have some very notice performance effects.

Fuel Injector Failure Symptoms

  • Cylinder misfires (most common sign)
  • Rough idling, poor acceleration, loss of power
  • Check engine light with engine misfire codes
  • Air-to-fuel ratios are either running rich or lean

The easiest way to tell that you have an injector problem is through the check engine light and engine codes for misfires. You will get cylinder-specific misfire codes which will point you in the direction of the bad injector. It’s worth noting that bad spark plugs and ignition coils can also cause engine misfires, so you might want to check these things prior to replacing an injector as injectors tend to be more expensive and difficult to replace.

3. 4WD Transfer Case Sensor Failure

Transfer case issues on the 4×4 Chevy’s and GMC’s go back to the 1990’s. Unfortunately, transfer case sensor failure has been reportedly somewhat commonly on all cars with the EcoTec3 engine. While this sensor isn’t necessarily engine related, it’s common enough in 2014-present models that it’s worth mentioning.

The transfer case is responsible for transferring powering from the engine to the front and rear wheels, through the driveshaft. On vehicles where you have 4×4 and rear-wheel drive options, there is a transfer case sensor that is responsible for controlling whether the truck is in 2-wheel or 4-wheel drive mode. When the sensor fails, the truck can get stuck in or out of 4×4 mode. Additionally, it is common for the truck to shift itself in and out of 4×4 without your control. This can lead to difficulty shifting gears, and noises from the transmission of the truck.

Failure Symptoms

  • Truck is stuck in 4×4, or won’t go into 4×4
  • 4WD Service light appears on dash
  • Noisy shifting gears, or difficult to shift gears
  • 4WD light flashes on and off intermittently

Fortunately, the repair here is as simple as replacing the transfer case sensor which is a rather inexpensive job. We recommend fixing this issue when it arises as continuing to drive can cause drivetrain issues if your car is frequently trying to switch in and out of 4WD while it’s moving.

4. Fuel Pump Failure

The 5.3 EcoTec3 has both a low-pressure fuel pump and a high-pressure fuel pump, or LPFP and HPFP. High-pressure fuel pumps are common failure points on virtually all direct injection engines.

These high-pressure pumps are also extremely stressed due to the heat and pressure they operate under. Over time it is common for the internal components to wear out and cause the pump to fail. Likelihood of HPFP failure is increased on trucks that are tuned, driven aggressively, or have performance modifications. The more horsepower your truck makes, the more fuel it needs to feed the engine. Therefore, the harder the HPFP has to work to deliver that fuel.

Fuel Pump Failure Symptoms

  • Long crank times
  • Engine won’t start
  • Engine malfunction light appears or service engine light
  • Reduced power and performance

5. Active Fuel Management Problems

One of the biggest issues with the 5.3L Vortec, and really all Cortec engines for that matter, was excessive oil consumption caused by the active fuel management system. The AFM system issues are one of the big reasons that GM transitioned to the new EcoTec3 engine family. AFM, also known as cylinder deactivation is where the engine shuts off 50% of the cylinders under certain driving conditions in order to improve fuel efficiency.

On the 5.3L V8, 4 of the cylinders are shut off, essentially making your truck a V4. The AFM system is known to cause excessive oil consumption issues. In addition to excessive oil consumption, the AFM can also cause the lifters to fail on the EcoTec3 engines, which is a rather expensive fix. AFM is good for maybe 10-15% improved fuel economy, but really isn’t worth it for all the potential problems it can create.

Is AFM still an issue? Yes.

While everyone hoped the EcoTec3 engine would fix the AFM issues, they still appear to be common. However, I would note that they appear to be somewhat less common that they were on the previous Gen III and IV vortec engines. Although this might be due to the fact that these engines are newer and less people are reporting problems as their cars likely still have factory warranty. The short answer is yes, the EcoTec3 engines still have AFM issues.

You can however prevent a lot of issues caused by AFM and DFM by simply disabling it. Using a plug and play device is completely undetectable and will keep your engine in V8 mode the whole time preventing problems and improving reliability.

Shop Boost AFM & DFM Disablers

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23 Comments

  1. Hi Mike,
    I wanted to do the same thing (force V8 mode) without having to buy a tuner for my Sierra due to changing my muffler to one that did not have the baffle installed. The droning sounds that the truck makes in V4 mode really bugs me.
    Anyway, to force V8 mode (deactivate AFM) all I do is shift past drive to M and arrow up to select 5th gear. The truck shifts normally through all 5 gears, but does not go to 6th gear and does not deactivate half of the cylinders.
    It works fine in the city and at speed I am maybe hitting 2500 RPM.
    I have used this method for the last 25k miles or more without issue and my truck is a 2014 Sierra 1500 All Terrain with 115k miles.
    I hope it works for you.

  2. They still have the issues. Had a 2015 gmc sierra slt 5.3 collapsed afm lifters three times.
    Yes that’s right blew up. You get one that is a lemon or a good one.
    GM just will not do a recall or fix them properly when under warranty.
    That’s also why they went to the 60,000 drive train later.

  3. My father was a GM owner and I have been a GM Chevrolet owner for most of my driving life. I am currently 61 and am looking to buy a new vehicle. Since the introduction of dynamic fuel management or skip fire if you like that term, I cannot see spending $60,000 on a truck or suv for that matter where the 5.3l engine has several known issues. The one that urks me the most is the collapsable push rods in these engines. The constant wear and tear on these components cannot stand the test of time and within 75,000 mile or less, the chance of a major cylinder misfire is a realization of many new owners and Chevrolet is turning their backs on them. I am looking at the Toyota Tundra or even Nissan. I do not like their looks but I can justify spending the same money knowing that the truck or suv will still be running way past the Chevrolet engine’s guaranteed failure. I am so disappointed in Chevrolet and their design. I would have bought one of these trucks or suv’s if the engine did not have the weak link push rods even knowing the miles per gallon would be 1 miles per gallon less in a perfect world. I even had high hopes when I read that due to the chip shortage they were sending them out the factory doors without DFM. Then I read that the engines still contained the weak link pursh rods. So, Good bye Chevrolet. I really liked your looks but your credibility and reliability have dropped out of sight and I need a dependable vehicle.

    1. So sad but so true. I would love to get one of the Chevies, but paying that price, forget about it. I know Ford and Ram are not to far behind on their problems too.

  4. I have a 2019 LTD Silverado with 113,000 well maintained miles and not abused. That mileage includes roughly 6,000 miles of towing a 3,000 lb bass boat and trailer. Anyway the engine spun cam shaft bearing. The fix was by a new engine as Chevrolet will not tear into a engine with over a 100k on it. Cost was $8,600. Oh I got a $200 visa card for the purchase. This is my 7th purchase of a new Chevy Silverado since 1996. I’m not yo sure if there will be an 8th.

  5. My 2015 Silverado 5.3 has 248,7000 trouble free miles. No AFM problems. Doesn’t use oil. Oh yes, I change oil every 3,000 miles. These engines CANNOT stand dirty oil. There are several very fine permanent filters built into the engine (eg, cam phaser, oil pressure unit to run the AFM, etc). Sludge will clog these components and cause them to fail. It is very unwise to extend the oil change intervals to the 7500 mile range that the on board computer will indicate. If you wait for the idiot light to tell you to change the oil, you will ultimately be changing the engine. And the real problem is dirty oil.

  6. Must have lived in that thing. And time to find new service dealer, they should do what ever you tell them to do. I’ve got both a 5.3 and 4.3. 5.3 is a young, ’19 with 25k. The 4.3 is a ’14 and has 195k with only suspension parts and brakes being replaced. Hilarious a fellow is talking collapsed pushrods and clearly hasn’t looked at OHC timing chain and cam tower issues (100k problems).

  7. I bought a new 2015 Serria 1500 4 wd 5.3 ltr I currently have 55000 on it carbon buildup problem had to have fuel induction cleaning at dealership $100 4wd sensor plugs and wires at 55000 miles several plug wires grounding out why I don’t know touching each other or toughing engine somewhere maybe improperly installed when made at factory new always have changed oil on reg basis.key on any engine folks fyi.*I’m told advised at dealership to use fuel addative cleaner to fuel systemto keep down carbon build-up.still on same brakes from purchase new I’m at 55000 miles just changed tires.battery went bad at 45000 miles mileage steady at 19 to 21 mpg.can anyone recommend best oil for my truck 2015 Serriaa 5.3 ltr 55000 miles.Older engines and body’s frames etc always outlast new junk.too much air pollution add on trying for more mileage etc.lets just lower gas prices and build more dependable vehicles like back in the day.the more you add to your vehicle the more problems you will have commonsense.stop with all the plastic parts.i had a Ford pinto wagon with a plastic adjuster nut for the clutch.bull s.trying to make everything lighter compromising safety dependability etc.if the vehicle parts components fail what’s the difference on fuel economy lighter cars and trucks ectif car won’t last.

  8. I’ve just got the p06dd oil pump failure on my mint condition 33,600 mile 2015 silverado 1500 and after reading about the future problems I have to look forward to this WILL be my last Chevy.

  9. Hello, I have a question.
    I have a 2014 with a L83 has a bad bearing with 158k. Can I install a L8B motor without making a lot of changes to the truck…

  10. My 2014 silverado lt 5.3 has 366,000. I did turn off afm at about 200k. Change oil every 10k with best filter k&n and always flush. Still doesn’t burn oil at all. Guess I got lucky. Thinking about refresh but maybe not . She is good.

  11. I have a 2014 GMC double cab SLE with the 5.3 L83 Ecotec version. 40,000 miles on odometer with no problems yet! From all the problems that are happening with the direct injection and AFM, I would like to swap for a GM older big block crate engine, but I don’t know if it can be done and is it a practical option?

    1. Is it possible, sure. Now practical is the bigger question – really depends on your budget and whether money matters or not. Swaps are $$$ so if you are looking for an affordable option this won’t be it. With only 40k on the clock I’d keep running it until you run into issues then you can consider a swap. Just drop an AFM disabler on it and you should be fine.

  12. Thanks Jake, for the comeback. The AFM disabler is only a computer resolution that would keep the 4 cylinders from shutting down. There is an AFM delete kit albeit more expensive but would replace the components that are the issue with the valve train. The Direct Injection is a major concern to me as well. The advantage of this design is to gain HP and fuel economy but to the detriment of reliability. GM in my opinion should back their new design (2014 on) with a better warranty if they believe in their design and engineered technology.

  13. Have 2015 GMC 1500 sierra 5.3 L Ecotech 3 v 8.
    January 2023 my engine light lit up. A service at the dealership I purchased the truck at did the work. The engine had less than 40000 miles. [unfortunately all warranties timed out!] Drove this truck responsibly – serviced at the dealership as recommended. The diagnostic check on the engine light reported problems with the injectors. Recommended fix was 1) – replace heads (injectors et al) or 2) replace with crate engine. I chose to replace the engine. It is going on to 10 weeks now with no delivery of the new engine. Anyone know how long it takes GM to fill the order?

  14. I bought a 2015 Chevy Silverado in 2018 . The truck had 23000 miles on it . I bought a 50000 mile extended warranty . My transmission went out at 80000. Luther Chevrolet called it a catostrophic
    failure . I don’t haul heavy loads or do any heavy towing . An occassional 4 wheeler or very seldom a boat
    . I was looking at buying a 2021 chevy or a 2020 ltz with a 6.2 . No more . Going to look at a Toyota . Sad to say . Chevy is chasing their loyal client base buy building crappy trucks with too many ongoing issue .

  15. 2021 Silverado 1500 WT with the 5.3L, Non AFM. At 36052 miles, 4 of 8 injectors failed. Not covered under 5/60 or extended warrantly. GM “helped” me out by covering 90%. Still cost me ~$300
    Not a happy camper

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