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2018 F-150 3.5L EcoBoost - Cold Start Rattle/Grinding Noise

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Mike T. · rep 0 · May 25, 1:32 AM · 1 replies · solved · Question

Vehicle: 2018 Ford F-150 Lariat

Hey everyone, I've got a 2018 Ford F-150 Lariat with the 3.5L EcoBoost engine and I've been experiencing a really concerning issue. On cold starts, especially after sitting overnight, there's a loud rattling or grinding noise coming from the engine compartment. It usually lasts for about 2-3 seconds and then disappears.

It sounds like it's coming from the front of the engine. Once the truck warms up, it doesn't happen again until the next cold start. The truck runs fine otherwise, no check engine light, but this noise is really making me nervous. Has anyone else with a similar year/engine experienced this? What could it be?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 1:32 AM

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ClearTheCode admin answer:

This cold start rattle on 3.5L EcoBoost engines, particularly in the 2015-2020 range, is a widely reported issue and is often attributed to issues with the Variable Cam Timing (VCT) system, specifically the cam phasers.

Common Causes:

  1. Cam Phaser Wear: The internal locking pins in the cam phasers can wear down, causing them to not lock properly on startup until oil pressure builds up. This results in the rattling sound as the cam phasers momentarily float.
  2. Oil Pressure Issues: While less common, insufficient oil pressure on startup can exacerbate cam phaser issues or indicate a problem with the oil pump or oil passages.
  3. Timing Chain Stretch: In some cases, a stretched timing chain can contribute to timing discrepancies and noise, though the phasers are usually the primary culprit for the specific cold-start rattle.

What to Do:

  1. Monitor: Note if the noise gets louder, lasts longer, or if a Check Engine Light (CEL) eventually appears. Common OBD codes associated with cam phaser issues include P0016, P0017, P0020, P0021, P0022 (indicating camshaft position sensor/timing issues).
  2. Oil Maintenance: Ensure you are using the correct viscosity oil (typically 5W-30 for this engine) and adhering to strict oil change intervals. Low or dirty oil can worsen VCT performance.
  3. Professional Diagnosis: It's highly recommended to have a qualified Ford technician diagnose the issue. They can perform specialized tests to confirm cam phaser operation and timing chain condition.

When to See a Shop:

You should see a shop as soon as possible. While many trucks run for a long time with this rattle, it can eventually lead to:

  • Reduced engine performance
  • Illuminated Check Engine Light
  • Potential for more severe engine damage if a phaser completely fails or timing becomes too far off.

Addressing it early can prevent costlier repairs down the line. A common repair involves replacing the cam phasers, and often the timing chain and related components, especially if the vehicle is still under an extended powertrain warranty or a Ford customer satisfaction program.

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