1999 Chevrolet Silverado 1500 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.

Chevy rolls out Silverado HD High Country

It's been a good week for heavy-duty truck buyers. First, Ram revealed the Black Package for its HD trucks, then it rolled out its new Power Wagon, and now Chevy's getting in on the action with its Silverado High Country HD. Okay, so it may not pack quite the attitude of Ram's latest 2500-series offerings, but the High Country HD will come as a welcome addition to the Chevy Trucks range to those looking to pull their horse, boat or other trailer without skimping on creature comforts.
Rolled out a little under a year ago, the High Country trim is Chevy's answer to the likes of the GMC Denali, Ford King Ranch and Ram Longhorn. It has until now only been offered on the light duty, 1500-series Silverado, but now extends to the 2500 and 3500-series HD models, as well.
So what sets a High Country pickup apart from lesser Chevy trucks? You'll be able to pick it out based on its chrome horizontal grille, body-color bumpers, 6-inch tubular side steps, 20-inch chrome wheels (18-inch on the 3500 and 17-inch on the dualie) and, of course, plenty of special badging. But it's inside where the High Country makes its mark, with a cabin decked out in saddle brown perforated leather, seats that are both heated and cooled, eight-inch touchscreen with full MyLink suite, Bose audio and park assist functions front and rear to keep those color-keyed bumpers looking fresh. (Though Chevy hasn't yet showed us the interior of the HD model, it'll presumably look mostly the same as the cab in the 1500 High Country in the gallery below.)

Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.