The most popular engine found in Chevy’s Silverado trucks is GM’s 6.2-liter EcoTec3 V8. Introduced in 2014, it continues in production today. Corvettes, and Camaro SS models, as well as its big SUVs, have a version of this engine. There are three common problems associated with the 6.2-liter, and also a smaller amount of lesser issues. We’ll look at many of them.
The 6.2 EcoTec3 came in six variations. Various versions have more problems than others, while some are common throughout. They are the L86 and L87 versions used in 2014-2018 Silverado and Sierra, 2014-2018 Yukon and Escalade, and 2014 to current Suburban and Yukon XL.
The L8T is a revised version of this engine, found in 2020 to current Silverado and Sierra HD models, and 2021-current full-size vans. And the Corvette and Camaro had LT1, LT2, LT4, and LT5 variations.
Chevy Silverado and GMC Sierra 3.0 EcoTec3 V8 carbon build-up
One of the main design features of the EcoTec3 V8 is direct fuel injection rather than port injection. With port injection, pressurized fuel is rammed into the cylinders, acting as a carbon flusher so to speak. With direct injection, there is no pressurization of the fuel. That eliminates this aid
This causes carbon deposits to collect in the intake ports. As the carbon builds, the air volume in the cylinders goes down. This results in issues you’ll recognize, like poor idling, inferior acceleration, engine misfiring, and richer fuel charges.
All direct-injection engine designs have this problem. But it normally develops around 75,000 miles on the ticker. According to Chevy Trucks, one way to lessen this problem is to buy an oil catch can system. This sloughs off the excess oil and deposits it into the can in the engine compartment. Less carbon buildup occurs because there is less unburned oil.
EcoTec3 V8 lifter collapse
Many engines have active fuel management systems. These shut off certain cylinders during certain conditions to improve mileage and lessen emissions. If you remember GM’s 4-6-8 cylinder deactivation in the 1980s, that was a crude version of today’s AFM. Unfortunately, after all of these years, it only works marginally better than that old, infamously bad system.
How it works is that “smart lifters” deactivate the camshaft from the cylinders. Unfortunately, these lifters tend to poop out and will collapse. When that happens, pushrods bend, which can begin a series of issues. At best, driveability is impaired. The good news is that an extended warranty usually covers the damage.
A8 automatic transmission issues
Most all 6.2-liter EcoTec3 engines are hooked to the A8 automatic eight-speed transmission. So this problem transcends only trucks and SUVs. It becomes immediately apparent within the first 20,000 miles there is a problem. You’ll notice engine vibrations and shuddering, and generally poor performance.
Rough gear changes from First to Second and then when shifting down from Second to First are immediately apparent. A GM Technical Service Bulletin places the blame on moisture in the transmission fluid used in assembly. It advises technicians to flush the system and replace the filter. If the problem persists, then GM will replace the torque converter as well.
Smaller problems that crop up on occasion include fuel injector and fuel pump malfunctioning, splitting engine mounts, broken manifold bolts, and lower intake manifold gaskets failing.