The GM 2.7-liter L3B Turbo four-cylinder engine for Chevy Silverado and GMC Sierra pickups is meant to change minds about power and torque in a small package. It seems this tough engine has everything incorporated into it. Stop-start cylinder deactivation, direct injection, variable valve timing, thermal management, and continuously variable oil pump; are just some of the Silverado features of the 2.7 Turbo to improve fuel economy and performance.
Available for full-size trucks starting in 2019, it continues into the current model year with a pretty good record. But problems have surfaced, which GM has addressed in various Technical Service Bulletins. So far, however, there have been no recalls.
With a long stroke increasing torque, that also can create certain vibrations. Built-in dual balance shafts help to override drivetrain vibrations. The engine has a cast aluminum engine block with iron liners.
What advanced fuel management systems are in the Silverado 2.7-liter?
This engine also uses what GM calls “Sliding Cam Valve Lift System” or SCS. This controls various lifter heights to save on fuel, depending on conditions. And this is combined with Active Fuel Management or AFM. In this mode, cylinders 2 and 3 are deactivated. Plus, all of this is also tied into continuously variable valve timing.
So there are the same components as 10 or 20 years ago, but now they’re doing more individual tasks. That also means there is more to go wrong, unfortunately. While the Silverado 2.7 Turbo is still fairly new as powerplants go, there have been some issues that are becoming more common.
In 2020, an updated L3B appeared, which addressed some issues. GM strengthened the engine block. Along with other changes, this allowed GM to increase the torque rating to 420 lb-ft. But Consumer Reports says that already, four percent of 2.7-liter engines have experienced catastrophic failures.
Carbon buildup in the Silverado 2.7-liter four-cylinder?
One issue that comes up with direct injection is carbon buildup. The fuel charge entering the cylinders is under much lower pressure than in past injection systems. That means the natural flushing of carbon that builds up on intake valves and cylinders is no longer possible with direct injection.
Most direct injection applications also have port injection, which counters this problem. All of the manufacturers recognize this issue, but GM chose to omit port injection for the 2.7 Turbo. So guess what? Carbon buildup is becoming a problem as these engines accumulate miles.
Carbon builds up over time, so engines hitting over 80,000 miles are showing up with issues. This includes less performance, rough idle, and misfiring. That’s because less air is able to enter the charge because there is less space.
Reports of Silverado’s poor fuel economy
Quite a few 2.7 Turbo owners are complaining about poor fuel economy. A class-action lawsuit against GM over lower fuel economy than advertised over its 5.3-liter Vortec engine is in the works. Now there is talk about the same for the 2.7-liter Turbo engine.
Those owners that are having this issue have seen an average fuel economy of about 19.5 miles per gallon. That’s two miles-per-gallon lower than advertised. With today’s gas prices, that amounts to over $12 on every fillup. In Cali, that would be over $14.
Lifter collapse is another issue
As with the GM 6.2-liter engine, there is a rise in incidents of lifters collapsing. This causes the cylinder when this happens, to stop functioning. Because the height of the lifters varies from ECU signals based on loads, it has to do much more work than your old small block Chevy engine. And there have been issues.
Again, this engine is in its infancy, and there are always issues with some new powertrains. So, we’ll keep an eye on the Silverado 2.7-liter Turbo engine to see if these problems manifest themselves, or if they are isolated incidents.