2013 Chevrolet Impala Ltz on 2040-cars

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Fullsize GM SUVs have a problem that's making owners sick

Some fullsize SUV owners are getting sick, thanks to a buffeting and vibration problem in 2015 model year examples of the Chevy Tahoe and Suburban, Cadillac Escalade, and GMC Yukon. According to owners' complaints to the National Highway Traffic Safety Administration, the issue can vary from an annoying vibration inside the cabin to an experience so severe that it leads to dizziness and headaches. General Motors is aware of the complaints, but the fix isn't so simple. According to spokesperson Tom Wilkinson to Autoblog, the company "has been tracking this issue for a while." The problem has a fairly low incidence rate, but when it does occur the issue can be "uncomfortable and annoying for owners." There's no precise cause for the issue, Wilkinson claims, and in some cases, simply balancing the tires or changing the door seals can make it go away. However, not all of the fixes are so simple. AutoGuide dug deep into the problem and discovered a GM preliminary information bulletin that advised dealers to remove the headliner and to check the roof's bonds to the bows that go across the vehicle. However, that document included a note that the solution might not entirely eliminate things. According to AutoGuide, adding Dynamat insulation to the roof sometimes helped the problem. A GM spokesperson also told AutoGuide the company fixed the problem at the end of the 2015 model year, and didn't go into any more detail. This roof issue seems linked to some of the worst droning in these SUVs. According to one complaint from a 2015 Suburban owner to NHTSA: "Roof will not remain attached to the roof bows. This causes the buffeting similar to a window being down when all are up. The results span from annoying to painful." A 2015 Yukon owner claims to have another alleged cause for the problem in a NHTSA complaint from February 2015. This person brought their SUV to the dealer seven times over the course of four weeks for vibrations. The dealer replaced the driveshaft, suspension components, and more, but nothing worked. According to an engineer to the service adviser: "In an effort to prevent roll overs, they designed the frame and body mounts too stiff. There are 40 engineers working on issues, they have no solutions that work across the board." Wilkinson told Autoblog that GM is working with customers on an individual basis to rectify things. Since these are newer vehicles, dealers should also fix the problem under warranty.

GM diesel pickups first to undergo extra EPA, CARB testing

The effects of Volkswagen's long-running diesel emissions evasion are starting to spill over to other automakers, but General Motors is taking things in stride. The 2.8-liter, four-cylinder Duramax in the 2016 Chevrolet Colorado and GMC Canyon is the first engine to get extra scrutiny by the Environmental Protection Agency and the California Air Resources Board, Automotive News reports. Rather than just the usual in-lab test, it's also being checked on the road. However, the extra evaluation shouldn't have any impact on when the trucks with his mill hit dealers later this fall. "We're in our final stages of the EPA certification, and our launch is on track," Chevy spokesperson Otie McKinley tells Autoblog. The four-cylinder diesel in the trucks makes 181 horsepower and 369 pound-feet of torque, and the automaker is touting low NOx production. In the announcement for the Colorado's specs, the company calls it "the cleanest diesel truck engine ever produced by General Motors." The tech includes exhaust gas recirculation to lower combustion temperatures and improve emissions. There's also a urea tank like on the bigger diesels for full-size trucks, and it gets refilled in time with oil changes. An indication on the instrument panel lets drivers know when that's needed, too. Even with the more demanding testing, the company doesn't seem too worried about the four-cylinder passing. "Part of our development process is on-road and off-road [laboratory] testing," Scott Yackley, Chevy Trucks assistant chief engineer, said to Automotive News. In the wake of the VW scandal, the EPA has pledged more rigorous testing. Before, on-road emissions evaluations were largely limited to heavy-duty vehicles, but the agency has decided to apply the checks more often to other models. There's also now greater cooperation with Canadian authorities.

Recharge Wrap-up: EV torque secrets, UC Davis maps future of biofuels

A UC Davis white paper maps out "Three Routes Forward for Biofuels," balancing investment risk with carbon benefits. The first option is "incremental," in which we tinker with the existing biofuel manufacturing infrastructure for small improvements over time. The "transitional" plan suggests integrating cellulosic production and other innovations with existing operations. The third route, called "leapfrogging," would mean building refineries based on new technology such as cellulosic and algae-based biofuels. The paper suggests ways the US could use these three routes together in different areas, and predicts the payoffs in terms of carbon emissions could be significant if the right people are willing to risk the capital. After all, financial advisers are always telling investors to diversify their portfolios to manage risk and rewards in the same way. Read more over at the UC Davis Institute of Transportation Studies. The Formula E Long Beach ePrix will offer free admission. The seventh round of the inaugural all-electric race season, which was moved from Los Angeles to the streets of Long Beach, will offer fans free grandstand and general admission. The race, which takes place on April 5, 2015, will use a 1.6-mile portion of IndyCar's Grand Prix of Long Beach. Read more at LA Times. Polaris is now offering its 2015 GEM electric vehicles, including the new street-legal eM1400 LSV. The passenger and utility vehicles come in two- to six-passenger configurations, many of which are street legal on roads with posted speed limits of up to 35 miles per hour. The eM1400 LSV utility vehicle seats two, offers 1,250 pounds of payload, 1,250 pounds of towing capacity, a top speed of 25 mph and a range of up to 45 miles. Its on-board charger plugs into any standard 110-volt outlet. Read more at Hybrid Cars and check out all the different configurations yourself at the Polaris website. In EVs, more torque does not always equal faster. Green Car Reports found this out when driving the Fiat 500e (with 147 pound-feet) against the similarly weighted Chevrolet Spark EV (with 400 pound-feet). The secret is, at least in part, in the gearing. The Fiat has a 9.6:1 reduction gear, making it quicker at lower speeds despite having far less available torque, while the Chevy uses a 3:1 ratio. The trade-off though, is in top speed. Furthermore, Chevy electronically limits the torque delivery at low speeds, as 400 pound-feet is a lot of launch for the little Spark EV to handle.