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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 under fire from safety advocates over braking problem caused by recall fix

Safety experts are lambasting General Motors over what they say is the automaker’s slow notification of owners of certain 2019 sedans and trucks that a recall fix could cause power braking to fail and increase the risk of a crash, the Detroit Free Press reports.  GMÂ’s original recall in December targeted about 550,000 Cadillac CT6 sedans and Chevrolet Silverado 1500 and GMC Sierra 1500 pickups, all from the 2019 model year, over potentially defective electronic stability control and antilock brakes. In that case, GM said the errors would not show up as a diagnostic warning on the instrument cluster. But after GM had done recall work on 162,000 vehicles, about 1,700 owner have complained that their power brakes didnÂ’t work after they had the recall done and then used the OnStar app to start their vehicle. GM then issued a supplemental fix for customers whoÂ’d already had their vehicles serviced. In this case, a diagnostic warning should illuminate saying either “Service Brake Assist” or “Service ECS,” which GM says is a signal that a customer should not drive the vehicle and instead call their dealer, which will tow the vehicle and have it repaired. Safety advocates say the automaker hasnÂ’t gone far enough to protect customers. “The fact that you could potentially start a vehicle and not have brakes is a pretty risky proposition,” Sean Kane, president of the Safety Research and Strategies, which works on auto issues for plaintiffs and governmental organizations, told the Freep. “The fact that they wouldnÂ’t notify owners (sooner) is pretty stunning.” GM told the Freep it was required to notify the National Highway Traffic Safety Administration and file paperwork before it notified customers about the original recall, which was made Dec. 12. It then had to investigate and resolve the problem created by its original recall fix before alerting customers. GMÂ’s call center and dealers are contacting the remaining 900 customers who havenÂ’t yet had the update made to the original recall repair. GM also hired a vendor to send recall letters to the 550,000 customers affected by the original recall notifying them about the update. There are no known injuries or deaths related to the problem. Read the Freep story here.

2018 GMC Sierra 1500 Buying Guide | What you need to know about this pickup truck

The GMC Sierra is a work-capable truck that can be optioned like a luxury car. Variety and choice are the keywords for the Sierra, not to mention close rivals like the Ford F-150, Ram 1500, and Chevrolet's own Silverado 1500. A Sierra buyer has a seemingly infinite list of choices when it comes to specifying exactly what they need in their pickup. In terms of cab length alone, there are three choices – Regular, Double, and Crew – to go along with your pick of Short, Standard, or Long cargo bed. Engines range from a 4.3-liter V6, upward to a range-topping 6.2-liter V8 available in top trim levels like the SLT and Denali. The Sierra can be ordered with a choice of two- or four-wheel drive, and transmissions include both a 6- and 8-speed automatic, depending on your choice of powertrain and trim. Changes for the 2018 model year include the standard fitment of a rearview camera, along with a Tire Fill Alert system that lets the driver know when the correct pressure has been reached. A 7.0-inch touch-screen stereo system is also now standard equipment on base Sierras. Is the 2018 GMC Sierra Safe? The National Highway Traffic Safety Administration gives the 2018 GMC Sierra 1500 an overall crash-test rating of five stars. In front and side impact tests, the latest Sierra 1500 scored a five-star safety rating. A four-star rating was recorded in the Rollover resistance test – this rating applies to Sierra trucks fitted with either rear- or all-wheel drive. Because the Sierra is such a popular vehicle, it's worth noting that the NHTSA conducted crash tests on models fitted with both these drivetrains, and in two cab lengths. The Insurance Institute for Highway Safety, which provides ratings for new vehicles based on its own comprehensive crash tests, also tested two versions of the Sierra 1500. The extended cab model registered "good" ratings in all but one of the IIHS' crash tests. Driver side protection in the small overlap test was deemed "acceptable" – front passenger-side results were not rated. Headlight effectiveness was given an "acceptable" rating, dependent on trim level selected. Meanwhile, the ease of use of the Child Seat Anchors (LATCH) was deemed "acceptable" in the extended cab Sierra. Ratings dip slightly for the Sierra 1500 in standard cab format. Driver-side protection in the front small overlap test drops to "marginal," while the available LATCH system scored a "poor" for its ease of use.