General Motors Will Replace L3B 2.7L Turbo I4 Truck Engines Produced With Cracked Blocks

GM L3B 2.7L Turbo I4 10 photos
Photo: GM
GM L3B truck engineGM L3B truck engine2023 Chevrolet Colorado2023 Chevrolet Colorado2023 Chevrolet Colorado2023 Chevrolet Colorado2023 Chevrolet Colorado2023 Chevrolet Colorado2023 Chevrolet Colorado
In production since 2018, the 2.7-liter turbo inline-four engine referred to as L3B has been hit with a customer satisfaction program. As it happens, a handful of engines may feature cracked blocks.
Under said customer satisfaction program, General Motors will replace the powerplants in certain 2023 model year Chevrolet Colorado, Silverado 1500, and GMC Sierra 1500 pickup trucks. Curiously enough, the 2023 model year GMC Canyon isn't affected. Unfortunately, it's not known how many L3B engines were produced with cracked blocks.

The program instructs Chevy and GMC dealers to perform the replacement at no charge until March 31, 2026. Beginning April 1, 2026, any applicable warranty will apply. The mid-sized truck and the full-sized 1500s are covered for three years or 36,000 miles (make that 60,000 kilometers) by the basic warranty. The powertrain warranty is listed as five years or 60,000 miles (100,000 kilometers).

Customer Satisfaction Program N232415060 is titled "Block Main Oil Gallery Hot Core Pin Casting Defect." Regardless of application, the L3B is cast by General Motors at Bedford Casting Operations in Illinois. The folks at Spring Hill Manufacturing in Tennessee are tasked with assembling the L3B.

An undersquare powerplant with a deep-skirt aluminum block, the 2.7-liter turbo inline-four mill further uses copper alloy exhaust valve guides, dual balance shafts, and a crankshaft offset from the cylinder bore centerline. Gifted with a nylon-reinforced plastic oil pan, the L3B is approximately 80 pounds (36 kilos) lighter than the American automaker's older 4.3-liter naturally aspirated V6.

GM L3B truck engine
Photo: GM
The 4.3er saw four applications to date, beginning with the 2014 to 2021 model year Chevrolet Silverado 1500 and GMC Sierra 1500. The other two are Chevy's large van and its GMC-branded cousin. Known as LV3 in truck applications or LV1 in GM's full-size vans, the 4.3-liter V6 is derived from the fifth-generation small block (a.k.a. LT series).

Similar to the LT series, the LVs and the L3B feature direct fuel injection. The only exception would be the C7-generation Corvette ZR1, which combines direct and port fuel injection. Still the most powerful series-production Corvette to date, the C7 ZR1 will be dethroned by the C8 ZR1, whose twin-turbocharged V8 promises more than 800 hp.

Despite being a four-cylinder lump with only 2.7 liters to its name, the L3B packs a considerable punch as well. For the Colorado, the Detroit-based automaker offers two specifications: 237 horsepower and 260 pound-feet (350 Nm) as standard or 310 horsepower and 430 pound-feet (583 Nm) for the TurboMax. The lesser spec is referred to as L2R in the order guide for the 'Rado due to a handful of different internal components.

The Silverado 1500 and Sierra 1500 come with the TurboMax by default. An eight-speed automatic is the only transmission available. Other than GM's mid- and full-size pickup trucks, the L3B can also be found in the Cadillac CT4 and CT4-V. A development of the L3B rolled out for the 2024 model year in the Chevy Traverse and GMC Acadia. Designated LK0, the newcomer is a 2.5 with 328 hp and 326 pound-feet (442 Nm) on tap.
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 Download: GM Customer Satisfaction Program N232415060 (PDF)

About the author: Mircea Panait
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After a 1:43 scale model of a Ferrari 250 GTO sparked Mircea's interest for cars when he was a kid, an early internship at Top Gear sealed his career path. He's most interested in muscle cars and American trucks, but he takes a passing interest in quirky kei cars as well.
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