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GM exploring ways to raise half-ton Duramax diesel tow rating

Lots of truck owners cheered when GM announced fuel economy numbers for the 2020 Chevrolet Silverado with the 3.0-liter Duramax diesel inline-six. Even after Ram let loose its EPA mileage ratings for the 2020 Ram 1500 EcoDiesel, the Chevy oil-burner still took the trophy. The victory was years in the making, GM engineers spending an entire four-year development cycle refining the LM2 Duramax to increase mileage. The tradeoff, as well all know by now, is towing; the Duramax in half-ton duty pulls a maximum 9,300 pounds in the Silverado. Rivals across town can do more, the Ford F-150 PowerStroke rated at 11,500, the Ram 1500 EcoDiesel game to pull 12,560. GM engineer John Barta told Muscle Cars & Trucks that more hauling chops could be on the way, explaining, "We’re actually looking at upgrading some of the materials around (the engine bay) to see if we can maybe raise our tow rating." Engine bay materials are at issue due to thermal complexities underhood. John Barta, GM's assistant chief engineer of diesel engine controls, said the Duramax's inline-six configuration allowed engineers to get emissions hardware like the combined selective catalytic reduction, diesel oxidation catalysts, and diesel particulate filter unit closer to the engine, where it heats up quicker, getting emissions down quicker. But that filter puts another heat source in those confines, enforcing a cap on the tow rating to keep the engine and other systems from overheating. "If you look under the hood," he said, "youÂ’ll see a significant amount of silver ‘moon tapeÂ’ around to make sure things arenÂ’t getting overheatedÂ… if we were to go up in higher towing, which we can, we start impacting the possibility of deteriorating some of the components.” There isn't much space for more grille, so swapping for a better grade of "moon tape" or a different kind of material could reduce engine bay heat, extracting a higher tow rating in the process.  It's important to note a point Barta's been making for months about the Duramax figures, though. "Even though itÂ’s nice to brag about big numbers, in reality, light duty customers are not towing that large with their trucks," and, "We do know that (95 percent) of our light duty customers donÂ’t tow over 9,000 pounds." On our First Drive of the 2020 Silverado diesel we called out the tow rating, but emphasized that the Chevy and GMC have more important challenges to overcome.

GM recalls nearly 340,000 large SUVs to fix daytime running lights

General Motors has initiated a recall campaign for more than 338,000 of its large SUVs to address a potential defect in the onboard computer software that controls the daytime running lights. In some cases, the DRLs may remain on even when the headlights are enabled, which creates additional glare for oncoming drivers at night and fails to comply with federal regulations for headlight performance.  "GM determined that the body control module (BCM) software in these vehicles, under a combination of certain pre-conditions, may fail to deactivate the DRLs when the headlamps are on," GM's recall report said. "A regulatory assessment was conducted to evaluate whether the condition presented a potential noncompliance with the DRL activation requirements in S7.10.5, Table I-a. of FMVSS 108. On October 27, 2022, GM’s Safety Field Action Decision Authority (SFADA) decided to conduct a recall for potential noncompliance with this standard." GM says the recall covers the 2021 model year GMC Yukon and Yukon XL, 2021 Chevrolet Tahoe and Suburban, and 2021 Cadillac Escalade and Escalade ESV. The company says all models produced within that operating window include the improperly programmed body control module, meaning all vehicles within the recall population may exhibit the problem. The issue was discovered by a GM engineer during validation testing in August, prompting a deeper investigation and eventually leading to the recall itself.   The module's software can be updated by GM dealers, so it should be a quick fix for customers. Notifications will be mailed to owners in December.  Related video: Recalls Cadillac Chevrolet GMC Ownership Safety SUV Luxury

2014 Chevrolet Silverado and GMC Sierra debut all-new designs, three new engines

General Motors has finally dropped the curtain on the 2014 Chevrolet Silverado and 2014 GMC Sierra. Both trucks have undergone substantial revisions with updated versions of the company's 4.3-liter V6, 5.3-liter V8 and 6.2-liter V8 engines. In a shot across the bows of both Ford and Chrysler, GM says it won't use a V6 engine adapted from passenger car applications. Instead, it developed the 4.3-liter engine based on its proven truck-duty architecture.
All three mills will boast direct injection fuel systems as well as a new cylinder head design. Combined with a revised piston, the new engines feature a smaller combustion chamber with a compression ratio of 11:1 or higher depending on the application. Cylinder deactivation and continuously variable valve timing are all part of the recipe, and each engine is paired with a six-speed automatic transmission with auto grade breaking. So far, no fuel economy or horsepower figures have been released, though GM says the new engines will best their predecessors in both areas.
Outside, the trucks feature a number of enhancements to reduce drag and wind noise, and GM claims both the Silverado and Sierra will offer buyers some of the quietest cabins in the class. Extended cab models now feature front-hinged rear doors to allow easier access to the back passenger area, and Crew Cab buyers can now select between a five-foot, eight-inch bed or a six-foot, six-inch bed. Buyers with a mind toward going off road will also rejoice in the return of the Z71 package, complete with Rancho shocks, front tow hooks and additional under-body protection.