James Sommer

2020 GMC Sierra AT4 6.2, purchased end of 2020 new 2-5095 K miles no oil issues 5095-10804 miles needed to add 2 quarts before scheduled oil change to bring up to full (oil add indicator came up on the DIC) 10804-15652 miles no issue 15652-19194 miles needed to add 1 quart to bring up to full (oil add indicator came up on the DIC) oil life monitor still shows 48% which means that I would not be due for an oil change for another 2 months or so. 19194-20600 miles DIC indicates add oil, oil life indicator reads 25%. 32K lifer knock, replaced all on left side 34K random misfire left side, fouled plug 34.5K noise, loss of power, black smoke, misfile and all types of engine messages New engine installed along with external oil cooler and all oil lines due to scores in the cylinder walls, scored bearings and cylinder #7 had all of the ring gaps within .25 of each other. Dealer had the vehicle almost 4 weeks and when I picked up it ran perfectly. Put on 4K miles and had the oil changed at the dealer to document that the service was performed and have my fingers crossed that this does not happen again. Within the first 1K miles I posted my best fuel economy if you are to believe the DIC numbers indicating that there were some issue with the original engine. GM would not extend the 5 year 60K drive line warranty as they replaced the entire engine. Although not as quite as my 2019 6.2 Yukon Denali the engine is very smooth and the idle is steady.