2007 Gmc Envoy Sle Sport Utility 4-door 4.2l on 2040-cars

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GM mulling off-road variants of fullsize SUVs

According to General Motors, owners "just love off-roading with [its fullsize body-on-frame sport utility vehicles]," namely the 2015 Chevrolet Tahoe and Suburban and GMC Yukon. If that's the case, it's a bit odd that sales of the previous generation of these models with the Z71 off-road package didn't sell particularly well.
Perhaps, considering this disconnect between owner's thoughts and desires with actual sales, it's not surprising that General Motors is reportedly "considering" an off-road specific model. That means the package would include styling changes and badges along with suspension modifications and larger wheels with appropriately sized fender flares.
There's no indication if the off-road model would be called Z71 or when it may potentially go on sale, assuming it ever goes on sale at all.

GM warning 800,000 owners that their cars may need oil changes more frequently than they say

The days of changing your engine oil every 3,000 miles are long gone thanks to most cars having automatic oil monitoring systems, but about 800,000 General Motors vehicles apparently have incorrect monitoring software that is leading to premature engine component wear. According to Autoweek, certain 2010-2012 Buick LaCrosse, Regal, Chevrolet Equinox and GMC Terrain models equipped with 2.4-liter four-cylinder engines could be going too long in between oil changes resulting in a higher-than-normal number of warranty claims for the engine's balance chain. The balance chain links the balance shaft to the crankshaft, and a worn one can produce higher noise levels.
As a fix, GM dealers will be reprogramming the software for the monitors in an effort to reduce the interval between oil changes, which varies based on driving habits and conditions. Through February 2015, the software update will be done at no cost to vehicle owners, but since this is not a recall, after that point, it will be up to the discretion of dealers as to whether or not they will charge for the service. What isn't immediately clear is whether GM plans on giving assistance to out-of-warranty customers who are experiencing engine issues from the worn chain.

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.