2003 Gmc Yukon Xl 1500 Slt 4x4 on 2040-cars

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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.

GM re-recalls 11k SUVs

General Motors is recalling a bunch of previously recalled SUVs because, well, they still aren't quite fixed. The latest repairs are necessary on 10,974 SUVs in North America, including 9,932 in only the US. Affected models include the 2006-2007 Buick Rainier, Chevrolet Trailblazer, and GMC Envoy; plus the 2006 Trailblazer EXT and Envoy XL. While not listed by NHTSA, a statement by GM to Autoblog says the 2006-2007 Saab 9-7X and Isuzu Ascender are also affected. In these SUVs, it's possible that liquid could get into the driver's door master power window switch module and cause a short circuit. This could potentially lead to a fire, and owners are urged to park the vehicles outside until repaired. GM has been trying to fix this issue for years. It started as an investigation into fires, and that led to a recall for about 250,000 vehicles in cold-weather states. A nationwide campaign came in 2013 for 193,000 of them in the US. Last year, the automaker decided to replace the whole module as a repair. However in a recent investigation of these recalls, GM discovered that this latest group of SUVs never received the new part. According to documents submitted to NHTSA (as a PDF), "Some dealers incorrectly used the labor code associated with module replacement when, instead of replacing the module, they only added a protective coating to the module." To fix things this time, the models finally get the correct component. Related Video: GM Statement General Motors is recalling 9,932 older midsize SUVs in the U.S. because they were mistakenly excluded from an earlier recall. Certain 2006 Chevrolet TrailBlazer EXT and GMC Envoy XL, and 2006-2007 TrailBlazer, Envoy, Buick Rainier, Saab 9-7X and Isuzu Ascender vehicles may continue to have a condition in which the printed circuit board inside the driver's door may corrode and short if exposed to certain fluids such as melted snow containing road salt. GM is aware of four fires but no crashes, injuries or fatalities associated with the expanded recall. The total number of vehicles being recalled, including Canada, Mexico and exports is 10.974. Customers are urged to park these vehicles outside until repairs have been made. GM reported this recall to the NHTSA on September 23.

GM readying aluminum-body fullsize pickups

Ford's extensive use of aluminum in its 2015 F-150 is a big deal. A really big deal. Big enough, in fact, that General Motors is reportedly changing its fullsize pickup strategy. According to The Wall Street Journal, The General has locked in partnerships with Alcoa Inc. and Novelis Inc. - companies that will supply aluminum for the next-generation Chevrolet Silverado and GMC Sierra trucks.
"Ford's introduction of the 2015 F-150 pickup truck was a game changer, and it's the first, not the last, conversion of this type," Novelis spokesperson Charles Belbin told the Journal. The switch to aluminum has allowed Ford to shave roughly 700 pounds off its fullsize truck's curb weight. And while official mileage ratings have not been announced, the weight loss should go a long way for improving efficiency, especially when combined other efficiency-minded improvements including better aerodynamics and new, turbocharged V6 engines.
Of course, aluminum-bodied cars are nothing new. But extensive use of aluminum in a major, best-selling product like the Ford F-150 is expected to kick off widespread use of this weight-saving material as availability rises and cost decreases. The WSJ reports that GM had originally explored the idea of moving to aluminum pickups back in 2008, but abandoned the idea due to cost concerns amid economic woes.