Crunch during cold start.

[Snail Style]

A/c compressor uses a valve to regulate itself, magnetic clutches are SO 2008. So that will not be causing your noise.

It could possibly be the cam positioner/adjustment valve, which would explain both the noise and RPM drop(rpm will rise/fall in relation to timing advancement or retardation).

There is a common issue with them, unfortunately that is how most warranty systems work. Before anything can be done, the fault has to be confirmed. What I would suggest to you is dropping the car overnight and then going in for the morning before they start it so you can demonstrate it. Usually the poor tech is only getting "Noise from engine when cold", so when they are testing it they are trying to hear a million different things.

Hope that helps.

[Umai Naa!!]

Yeah, once you've told the service advisor of your concerns, it's all Chinese Whispers from there.

[thewafflecaust]

Have tried leaving it for 30 minutes a couple of times but it seems to only happen when the car has fully cooled down. Long enough that my car does that high idle thing to warm up. Would the cam adjuster cause a drop in revs?

As others have suggested, leave the car with the service center overnight/for the day and have them start it from cold.

I don't remember if mine dropped in revs much, but everything you describe sounds the same as the problems i had.

[jameshero]

As others have suggested, leave the car with the service center overnight/for the day and have them start it from cold.

Will have a chat to them on Monday and organize a time to bring it in.

Thanks again for your help