2018 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 2015-2018 Chevrolet Suburban, 2015-2018 Chevrolet Suburbans are covered by GM safety recall 19V645000. GM determined the vacuum produced by the vacuum pump may decrease over time, and the brake booster depends on that vacuum to do most of the work of applying the brakes. On a vehicle as heavy as the Suburban, losing assist matters: NHTSA states that as the vacuum level drops, braking effort increases and the distance required to stop the vehicle extends, raising crash risk. The condition builds gradually, so it is easy to adapt to a stiffening pedal without recognizing it as a defect. The recall's 3,456,719 units affected is a campaign-wide total covering all the GM trucks and SUVs named in it.

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 2015-2025 Chevrolet Suburban, the 2015+ Suburban uses an electronic steering column lock that can malfunction, causing a clicking noise from the steering column, failure to recognize the key fob, or preventing the vehicle from starting. The electronic lock module replaces the traditional key-cylinder lock and communicates with the body control module (BCM) to verify the key fob is present before allowing the engine to start. When the lock module fails, it may click repeatedly without unlocking, or it may not engage at all, leaving the steering unlocked even when the vehicle is off.

On the 2000-2025 Chevrolet Suburban, the transfer case on the 4WD Suburban develops fluid leaks from the front and rear output shaft seals, the input shaft seal, or the case halves where the case splits. The NP246 (half-ton) and NP261/NP263 (heavy-duty) transfer cases all share this tendency. On the NP246 (Autotrac) case, low fluid causes the internal clutch pack to overheat and burn, and on any case low fluid leads to expensive internal damage. The rear output seal is the most common leak source, and the leak often drips onto the exhaust, creating a burning fluid smell. Many owners do not realize the transfer case has its own fluid that needs periodic changing.