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Failure mode - Ford 3.5L EcoBoost Gasoline (F-150, Expedition, Transit, Raptor - 2011-present)
Timing chain stretch / guide wear (Gen1 era)
Reliability tier: aggregated - verify before ordering, see /disclosure/
Symptoms
- chain rattle/slapper noise at start-up or under light load
- MIL with cam/crank correlation DTCs
- progressive rough running as correlation drifts
- metal finding in oil on advanced cases
Compare with the other causes of the same sign on this engine: ticking, knocking, rattle or whine (4 causes) · misfire, rough idle, hesitation or surging (5 causes) · metal in the fuel filter or oil
Root cause
Gen1 chain-drive hardware (guides/tensioners) wears with mileage and oil-interval history; Ford issued a MY2011-2014 3.5L GTDI MIL/correlation bulletin. Advanced cases shed guide material and lead to long-block decisions.
Diagnosis
- listen for chain slap vs phaser rattle (chain noise tracks rpm, phaser noise is start-up transient)
- scan for P0016-family correlation DTCs on both banks
- inspect guides/tensioner through the service access before committing to a chain job
- check oil-change history - extended intervals dominate the owner reports
Fixes
timing chain, guides and tensioner replacement with phaser inspection; long block if guide debris advanced ()
- timing-chain - more than one option: 3.5L EcoBoost Timing Chain (AT4Z-6268-C), 3.5L EcoBoost Timing Chain Guide (AT4Z-6B274-A), 3.5L EcoBoost Timing Chain Tensioner (BL3Z-6L266-A)
- 3.5L EcoBoost Service Engine Assy / Long Block, Gen1 (DL3Z-6006-ARM)
- 3.5L EcoBoost Cam Phaser / Timing Actuator (AT4Z-6256-B)
Prevalence
common