P0022 on Ford

Multiple Bronco owners report a brief but pronounced rattling or knocking noise on cold start caused by worn or defective cam phasers, often accompanied by timing chain slack. Ford issued service guidance for EcoBoost engines using updated phaser parts. While some vehicles only exhibit noise, others progress to rough running, check-engine lights, or repeat repairs if only partial components are replaced.

The 3.5L/3.7L Duratec V6 in first-generation Ford Edge commonly develops timing chain stretch and variable camshaft timing (VCT) phaser rattles between 80,000-120,000 miles. The engine uses two timing chains (one per cylinder bank) that can stretch over time, causing the VCT phasers to rattle loudly on cold starts as oil pressure builds. The rattle typically lasts 2-5 seconds on startup before oil pressure stabilizes. Left unaddressed, chain slack can cause timing to jump, resulting in rough running, poor fuel economy, and potential catastrophic engine damage if a chain breaks or a guide fails.

On the 3.0L Duratec V6, the camshaft bearing cap bolts — particularly the rearmost caps — work loose on their own over time. Owners on escape-city document caps found well under specified torque during valve cover gasket jobs on cars with no prior top-end work. As the cap loosens, the camshaft journal loses its clamp load: the engine develops a rattle or tick from the top end, oil pressure at the cam journal drops, and the variable cam timing phaser starts behaving erratically, throwing cam timing correlation codes. If left alone, a cap bolt can back out or snap, which lets the cam walk and destroys the head. It compounds a second well-known 3.0L weakness: the valve cover gasket leaks oil onto the alternator, and shops that replace the alternator without curing the leak see it fail again. This is 3.0L Duratec V6 specific — it is not a failure of the 2.0L Zetec, the 2.3L or 2.5L four-cylinders.

The 2nd-generation 3.5L EcoBoost V6 in 2018-2022 Ford Expedition (Gen 4) addressed the timing chain stretch issue of early-generation 3.5L EcoBoost engines (2011-2016) but introduced a new problem: VCT (Variable Camshaft Timing) unit wear that causes a distinctive ticking/tapping rattle on cold starts after a 6+ hour soak. The rattle typically lasts 2-5 seconds and comes from the top front of the engine. Ford issued TSB addressing the condition for 2018-2019 Expedition/Navigator, recommending VCT unit replacement. The cam phasers become sticky when oil drains back overnight, then rattle until fresh oil pressure reaches them.

The 5.0L Coyote V8 can develop a ticking or rattling noise at startup, often from the cam phasers. This is similar to issues in the Mustang GT. The noise typically diminishes after the engine warms up but can indicate phaser wear.

Two distinct tick patterns affect 5.0L Coyote V8 in 2015-2023 Mustang depending on engine generation. Gen 2 Coyote (2015-2017): light tick at idle and on cold start, commonly attributed to valve lash / lifter operation; generally cosmetic and not associated with engine damage. Gen 3 Coyote (2018-2023): louder, more pronounced tick — same family but Ford changed to plasma transferred wire arc (PTWA) cylinder liners. The tick is increasingly linked to piston slap from clearance issues against the plasma liner, with some confirmed cases of cylinder wall scoring requiring engine replacement under warranty. Direct injection (added on Gen 3 alongside port injection) contributes a separate fainter HPFP tick that is normal. Distinguishing: Gen 2 tick stays constant warm; Gen 3 piston slap diminishes as engine warms but returns under load. Owner forums (Mustang6G, MPR Racing Engines) document the Gen 3 pattern extensively.

The 3.5L Duratec V6 in later model Taurus vehicles develops cam phaser rattle on cold starts due to worn variable valve timing actuators and depleted oil control valve seals.