I have owned and or worked on just about every large GM SUV made. I am also a ASE certified master tech. This being said the 5.3 is not a bad motor, but the 6.2 found in the Escalade and Yukon Denali is the better choice for towing imho. Fuel mileage is virtually identical to the 5.3 but does require premium fuel in the 6.2 . The 6 speed transmission found in the 2008 to 2014 is a far better transmission for towing the the old 4 speed found in the earlier years. We have seen our fair share of intake leaks on the 5.3, but none yet on the 6.2, we have also seen a ton of 5.3's with oil consumption issues, yet none of those issues on the 6.2. The torque of the 6.2 Denali that I just sold which was a 2011 was FAR and away superior to my 2015 Toyota Tundra platinum crewmax with a 5.7 and a 4.30 rear differential. The auto ride on the Denali was also far superior to the suspension on my Tundra. Remember though that the electronic shock absorbers and front struts on the Denali and the Escalade are around $450 per shock from the dealer, and we have seen a "**** ton" of them go bad! My last straw on my Yukon was when the dashboard cracked by the passenger side airbag and also above the steering wheel. The cost to repair that alone is over 1k,! I live in PA, and we use road salt and that did not do anything positive for any of my Yukons! All 08, 09, and 2011 all had rusting problems on the bottoms of the doors, and rear lift gate! This is thanks to GM using Chinese steel and refusing to use seam sealer on their outer door skins! We have also seen a ton of 5.3, and 6.2's with broken exhaust manifold studs on the drivers side rear of the cylinder heads. This is again an expensive repair in the neighborhood of $1k. My 2011 had rear a/c lines beginning to leak as they are made of aluminum and run under the truck in steel clamps which when combined with road salt = massive corrosion! As a person who fixes cars for a living I HATE working on my own stuff, that's why I buy new and keep it 3 years and done! These trucks will last 60k trouble free on average, THEN GM's cost cutting methods will rear its ugly head! Rusting in out environment is common, chrome wheels that flake off into finger slicing sheets of pealing chrome are common, front inner chrome over plastic door handles that flake and again cut the hell out of people are also common issues! When my dash cracked on the 2011 in the same exact place as my 2009 did with only 50k miles on it and the dealer and GM both said sorry, out of warranty, I gave them both the same answer, "not only will I never ever buy another one of your vehicles, but I will never recommend your vehicles to ANY of my customers for this very reason! There is a damn good reason why these Denali's and Escalades can be purchased at 50% of their original value in 3 years time, when their foreign competitors are retaining 70 to 80% of their value at that same age. You are getting what you pay for! All of this being said my Denali towed my 7600lbs boat with ease, much better than my new Tundra does, the electronic shocks are amazingly good at calming the bounce of the ride for a large SUVs, the rear air shocks make it seem as if there is no boat back there! Just watch out for the things I have pointed out earlier in my post and you should be fine. I would never buy one with 100k plus miles on it and think I am going to have a trouble free vehicle, there are going to be issues, that a given. The alternative is to buy brand new and let me tell you the payments suck...lol
I've got 118K on a 2009 and that is more normal mileage for a truck/suv if you are looking at the market.
