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Problem is that engine, 1.6 16v K4M, makes strange noise at start up. Engine is producing this sound when it is cold and not driven for 12 or more hours.

https://youtube.com/shorts/4A4hQshoIeY?feature=share

Any ideas? Thanks

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  • Welcome to Motor Vehicle Maintenance & Repair! Commented Aug 17, 2023 at 14:15
  • It seems you've taken the video down so I can't hear the noise. However my first guess would have been something wrong with the dephaser pulley/solenoid as it's a very common issue on the K4M. I would suggest you check if your engine is one of the variants with VVT that would be susceptible to this issue
    – James
    Commented Jan 16 at 9:34

2 Answers 2

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Something that sounded just like your sound happened on a family car. It only happened when my wife started it, but never when I started it.

Careful observation revealed that my normal practice when starting a car is to turn the key to Start, and when it catches, turn the key back to Run.

When my wife started the car, she would turn the key to Start, and when it catches, she would release the key and let it turn back to Run on its own.

Except it wasn't turning back on its own -- it was sticking on Start and the starter's pinion gear was remaining engaged with the flywheel's ring gear and making an awful racket.

It was an older car and the dielectric grease inside the ignition switch was dry and sticky. This only happened when the car had not been started for some hours, because the ignition switch would get warm in use and the grease would become thinner when warm and would not stick.

So you can start diagnosing this by manually and vigorously returning the ignition key to the Run position when the engine catches. If the sound stops happening, the ignition switch is probably sticking and you need a new one.

If this is not a solution, look for some other reason that the starter's pinion gear is remaining engaged after the engine starts, such as thickened grease in the starter or a broken solenoid spring.

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That sounds like a rattling cam follower due to a lazy hydraulic lifter.

Oil pressure is used to lift the cam followers into the correct position against the cam shaft. If one of the hydraulic lifters is faulty and not responding quickly, it can leave a big gap between the camshaft and the cam follower. This can cause a cam lobe to slap the cam follower creating this noise. Once the oil pressure has built up enough to make the hydraulic lifter to move, the noise goes away.

You likely need to replace at least one of the hydraulic lifters. However other than the brief noise, it is probably not causing any issues at the moment.

wikipedia - Hydraulic tappet

The reason the noise only occurs after long periods of not running the engine is due to the oil slowly leaking out of the hydraulic lifter.

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  • Hear hoofbeats, think tappets, not ignition switches. Good answer!
    – MTA
    Commented Aug 18, 2023 at 11:42

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