2012 Chevrolet Suburban Problems: 5 Known Issues

On the 2007-2025 Chevrolet Suburban, the Active Fuel Management (AFM) and Dynamic Fuel Management (DFM) systems on the 5.3L and 6.2L V8 engines deactivate cylinders to save fuel by collapsing hydraulic valve lifters. These lifters have a complex locking pin mechanism that fails, causing the lifter to collapse and the affected cylinder to misfire. A collapsed lifter can also damage the camshaft lobe it rides on, turning a $300 lifter into a $3,000 camshaft and lifter replacement. The issue affects 2007+ Suburbans and is one of the most complained-about GM V8 problems. The Suburban switched from AFM to DFM with the 2021 redesign (5.3L L84, 6.2L L87), but lifter failures continue.

On the 2007-2014 Chevrolet Suburban, the 2007-2014 (GMT900) Suburban's steel brake lines have a much better coating than the 1999-2006 trucks. GM switched from an aluminum-rich paint (AlGal) to an extruded nylon outer layer (NyGal) that NHTSA describes as about 50 times thicker and more resistant to stone chips. The lines are still steel underneath, though, so years of road salt can eventually corrode them. NHTSA's investigation of the earlier GM trucks found that this kind of corrosion was general wear-out across most of the line set rather than a defect in one spot, and that failures began to appear after roughly 7 years in salt states. These trucks have two separate hydraulic brake circuits. If a line rusts through, it can leak with little warning and leave you braking on only one circuit, which makes stopping distances much longer.

On the 2007-2020 Chevrolet Suburban, the Suburban has a rear A/C system with refrigerant lines that run the full length of the vehicle underneath, exposed to road salt, debris, and moisture. These aluminum and steel lines corrode through, especially at the connections and where the lines are clamped to the frame. When a line corrodes through, the entire A/C system loses its refrigerant charge and both front and rear A/C stop working. The rear lines are particularly vulnerable because they are in the splash zone behind the rear wheels. This is a widespread issue in northern salt-belt states.

On the 2000-2025 Chevrolet Suburban, on 4WD Suburbans, fluid can leak from the transfer case at the front or rear output shaft seals, or from the seam where the case halves bolt together. One technician reported a 2001 Suburban 5.3L with the NP8/246 transfer case that kept leaking from both output seals after the seals had been replaced twice and the case rebuilt. Owners of GM SUVs with the same NP246 case report a repeat leak at the rear output seal, where the rear driveshaft slip yoke slides in and out of the case. If the yoke surface is rough or wavy, it can wear the new seal, so the leak can come back after a seal-only repair. Owners of 2000-2006 models also report leaks at the seam where the rear section bolts to the main case, which is sealed with silicone. On 2015-2024 models, GM bulletin 22-NA-225 says red fluid near the rear of the transmission or transfer case may not be a case seal at all. It can come from the welch plug in the front propeller shaft slip yoke. The transfer case has its own fluid, separate from the transmission. If the level runs low, the case can be damaged.

On the 2007-2014 Chevrolet Suburban, the dashboard on 2007-2014 Suburbans develops extensive cracking across the top surface due to UV exposure and heat cycling. The dashboard material shrinks and hardens over time, causing deep fissures that spread across the full width of the dash. The cracking is worst in southern and southwest states with intense sun exposure, but affects vehicles nationwide. GM was the subject of multiple class-action lawsuits over this defect across the GMT900 platform (Tahoe, Suburban, Silverado, Yukon). The cracked dashboard is a cosmetic and resale value issue.