The 5.3L L83 and LMG V8 with Active Fuel Management (AFM) is one of the most problem-plagued GM engines of the last decade. Collapsed lifters on the AFM cylinders (1, 4, 6, 7) routinely strand owners with $3,500-$7,000 repair bills - and class-action lawsuits are still working their way through the courts.
High failure rate. AFM lifter collapse is widespread on 2014-2019 5.3L V8s. Expect lifter or cam work between 80,000 and 150,000 miles. Class-action litigation is active.
The AFM lifters on the deactivating cylinders fatigue, collapse, and chew up the cam lobe. You will hear a hard tick at idle and throw misfire codes on cylinders 1, 4, 6, or 7. Most shops replace all 16 lifters and the camshaft together.
View P0301 Diagnosis →The AFM oil pressure relief valve in the valley pan clogs or sticks open, starving the lifters of oil. This is the root cause behind most lifter failures - and the cheap fix that should be done before damage starts.
View P0521 Diagnosis →Burning 1 quart per 1,000-2,000 miles is common. Same root causes as the LC9 - piston rings and PCV behavior. Often overlaps with AFM lifter symptoms.
View P0507 Diagnosis →Misfire codes on the AFM cylinders are the early warning sign of a collapsing lifter. Do not just throw plugs and coils at it - pull a valve cover and inspect.
View P0306 Diagnosis →Once a lifter collapses, the camshaft lobe gets eaten in short order. Driving more than a few hundred miles with the tick almost guarantees a cam replacement.
View P0014 Diagnosis →Direct-injection 5.3L engines build carbon on the intake valves over time. Causes rough cold start and small power loss around 80K miles.
View P0171 Diagnosis →Run a free AI diagnosis tailored to your exact vehicle. Get the most likely cause and repair estimate in under 30 seconds.
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2014-2019 5.3L L83/LMG with AFM. The 2014-2016 trucks have the highest reported lifter failure rates.
2020+ trucks switched to DFM (Dynamic Fuel Management) - early data is much better. 5.3L L84 (2019+ truck) avoids the L83 lifter pattern. Or look at the 6.2L L86 - similar AFM design, much lower failure rate.
Plan on a $4,000-$6,000 lifter and cam job somewhere between 100,000 and 150,000 miles unless you AFM-delete early. AFM delete tunes plus a non-AFM valley pan and lifters run $1,200-$2,500 installed and effectively eliminate the failure mode.
If your 5.3L is throwing a check engine light, these are the codes most often associated with the problems above. Click any code for full diagnosis steps and typical repair costs.
Yes. Multiple class-action lawsuits are pending against GM over 2014-2019 5.3L AFM lifter failures, including cases consolidated in federal court. Coverage depends on your state and your truck.
Expect $3,500-$7,000 at a shop. Most jobs include all 16 lifters, the camshaft, head gasket, and labor. DIY parts cost is around $1,200-$1,800.
An AFM delete uses a tune to disable AFM and a non-AFM valley pan plus standard lifters to physically remove the failure-prone parts. It costs $1,200-$2,500 installed and effectively eliminates the lifter failure pattern. Most owners do it preventively.
2014-2019 Silverado 1500, Sierra 1500, Tahoe, Suburban, Yukon, and Yukon XL with the 5.3L L83 (truck) or LMG variants.
Most failures cluster between 80,000 and 150,000 miles, but failures as early as 40,000 miles are documented. Highway-only trucks often last longer because AFM activates more often than in stop-and-go driving.