Notice A Rattling Sound In Your F-150 EcoBoost? Find Out The Cause Of The EcoBoost Knock.
Do you hear rattling noises coming from the 3.5L V6 EcoBoost engine in your F-150? While the EcoBoost has proven reliable overall, some issues have persisted since Ford introduced the engine. One problem is a rattling noise that occurs at startup. Ford has issued several remedies and technical service bulletins (TSBs) over the years with mixed results.
What Causes The F-150 EcoBoost Rattle?
The 3.5L EcoBoost is prone to a couple of issues that may cause a rattling noise. The first-generation (2011-2016) and second-generation (2017-present) 3.5L V6 EcoBoost engines could suffer from noises caused by:
- Timing Chain Stretch
- Cam Phaser Play
The first-generation EcoBoost primarily had issues with timing chain stretch. EcoBoost uses variable valve timing (VVT) to optimize for fuel economy or power based on driving conditions. VVT includes cam phasers that control the position of the camshafts relative to the crankshaft. Ford refers to their system as Twin Independent Variable Camshaft Timing, or TI-VCT. The EcoBoost has four cam phasers, with an intake and exhaust cam phaser on each cylinder bank. As the timing chain stretches, the cam phasers can’t keep engine timing within specifications. The engine control unit (ECU) sets diagnostic trouble codes (DTCs) and turns on the check engine light. If the chain stretches enough, the slack can cause a rattling sound on engine startup.
The second-generation EcoBoost had a condition where the cam phasers would cause a rattle on startup. Oil pressure controls the adjustment of the cam phasers. The cam phaser design includes a locking pin to hold each cam gear at the base timing location during engine shutdown. Sometimes the pins don't engage as the engine shuts off. Without the locking pins engaged, the cam phasers can move freely before enough oil pressure is available to the TI-VCT on engine startup. This play in the cam phasers will cause the timing chain to rattle until there is sufficient oil pressure.
The engine oil filter can also cause the cam phasers to rattle on startup. If the oil filter does not have an anti-drain back design, most of the oil can drain from the filter into the crankcase when the engine is shut off. Without oil retention in the filter, it takes longer for oil pressure to build up when starting the engine, causing the cam phasers to rattle. OEM oil filters have this feature, but many aftermarket filters do not.
What Is The Fix For Knocking In An EcoBoost?
Image Credit: FordAuthority
Ford has released many TSBs and production fixes over the years, including reprogramming the powertrain control module or replacing the timing chains and cam phasers. However, these solutions appear to be only temporary fixes for the rattling noise. According to many owners, the rattling problem either remains or goes away temporarily, returning over time.
In the meantime, Ford has continued making production design changes to the cam phasers with several part number changes. Owners have resorted to their own workarounds to avoid costly out-of-warranty engine repairs. One trick is allowing the engine to crank longer before startup. The purpose is to reduce the severity of the rattle by building up oil pressure before the engine starts. This only works on F-150s with push-button start.
To get the engine to crank longer before starting, depress the brake and accelerator pedals simultaneously while pushing the start button. As long as both pedals are applied, the engine will crank without starting. Keep your foot on the brake pedal while releasing the accelerator pedal and the engine will start. Of course, this only masks the problem and is not a long-term solution.
What Should I Do About The Problem?
Ford has had some customer satisfaction campaigns to address issues with the 3.5L V6 EcoBoost. If you’re the current owner of an F-150 with this engine, ensure your Ford service department has completed all available TSBs or campaigns to address the engine rattle. Research the vehicle history beforehand if you want to purchase a used F-150 with an EcoBoost engine. Listen for unusual engine noises on cold startup and request a service record of the truck to determine if Ford dealers have completed applicable warranty repairs. You can also check out this post to learn more about the three most common turbocharger problems.
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