Has your 3.5 Eco boost started making a very annoying rattling noise? Does it usually happen on cold-start after the truck has been standing for a few hours? This phenomenon is synonymous with Gen 2 F150s with mileage close to 30000 mi or more. The good news is that it’s not catastrophic and there is a quick explanation and DIY solution to your problem, so keep reading.
Gen 2 Ford F150 trucks are reported to emit a rattling noise when the phaser duty cycle in the PCM (Power Control Module) calibration causes premature wear of the phaser locking pin. When the phasers don’t lock properly it causes them to rattle until there is sufficient oil pressure to fill the VCT (Variable Camshaft Tuning) unit.
This is a known issue and Ford should repair it under warranty.
Now that we have the technical explanation of what the cause is, let’s now look at the solution in more detail and later what DIY fix we have to prevent the rattle upon cold start.
Why Does My F150 Rattle When I Start It – DIY SOLUTION
The next section explains in a bit more detail what happens with the cam phasers then we look at a quick 6-second DIY fix and later what real-world Gen 2 F150 Owners have to say about the rattle noise.
Option #1 – Cam Phasers
What are Cam Phasers and what job are they designed to do? Basically, Cam phasers are located in the head and are designed to lock at base timing after shutting down. Why is this important? It’s important because this allows time for oil pressure to build in the heads on the next cold start. How does this happen? The oil pressure unseats the locking pin and the PCM (Power Control Module) can then control the phaser position via the VCT solenoid.
What happens when the phasers don’t lock properly? When the phasers don’t properly lock, they rattle until there is sufficient oil pressure to fill the VCT unit.
Quick test: How to Perform the Extended Cranking
You can force the engine to build sufficient pressure by holding the gas pedal to the floor and simultaneously turning the key for about 6 seconds. Do this after a few hours of standing or on your first-morning start-up. By depressing the gas pedal and starting the ignition, it will swing the starter without allowing the engine actually to start.
What does this do? It will allow the engine to build enough oil pressure. After about 6 seconds, let off the gas and turn the key again. If you don’t hear the startup rattle then the problem is confirmed to be your cam phasers.
Option #2 – The Cause
It’s a very technical explanation and I’m no qualified mechanical engineer, but I’ll try to explain it in lemans terms regarding what causes the rattling noise.
Basically, there’s a pin that gets worn out prematurely. The issue is that the phaser duty cycle in the PCM calibration was causing premature wear of the phaser locking pin. On cold-start, the phaser would be at base timing with the locking pin engaged. Oil pressure regulated by the VCT solenoid unseats the locking pin and allows the phaser to adjust timing. If the locking pin is worn the phaser will rattle until oil pressure fills the oil cavities.
Option #3 – The DIY Fix
By carrying out the above DIY process, you are simply masking the issue by allowing or forcing the engine to build oil pressure before it starts. This eliminates the rattle noise, temporarily.
As mentioned previously, Ford is aware of the problem and released a TSB to rectify all vehicles under warranty.
(WATCH) 3.5L Ecoboost F150 Rattle On Startup Then Gone – VIDEO
Watch Ford Boss Me below for a clear explanation of the cause as well as the DIY Startup procedure.
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FORD F150 Owner Experience/Feedback
F150 Owner Experience/Feedback #1
F150 Owner Experience/Feedback #2
F150 Owner Experience/Feedback #3
To perform this extended cranking, for about 6 seconds, depress both the brake and gas pedal and push the start/stop button. The engine will continue to crank for as long as the gas pedal is held down. Once you release the gas, the engine will start normally and shouldn’t rattle.
Vehicles without the keyless start, perform the same brake/gas pedal procedure but turn the key and hold it. Let off the gas and key, and the engine will start normally.