[zummrox]

Whenever i cold start my 2014 320i x drive, there is this metallic rattle noise coming from the engine bay. This sound lasts for about a minute and goes away. It goes away quicker as you rev the engine - seems to be linked to engine temperature. Never does this when starting the engine warm.

Can anyone point in the direction to what this is? I don't remember hearing this when i first got the car. See video below:

[lacrimarum]

It sounds to me like it's a wastegate rattle.

[zummrox]

Originally Posted by lacrimarum

It sounds to me like it's a wastegate rattle.

I've heard this before too. What is wastegate? something i should be concerned about?

[ToniD]

would like to know as well.

[lacrimarum]

Originally Posted by zummrox

I've heard this before too. What is wastegate? something i should be concerned about?

A wastegate is a valve of a turbocharger, through which compressed air bypasses in order to regulate boost pressure. In my experience, if it operates significantly wrong, engine control unit will instantly write an error and shutdown turbocharger. So I'd suggest you to check for errors (in independent shop or you could even do it yourself). If there are none, and you never notice any power losses, then it's quite possibly nothing more than sound, and there's not much to worry about.

[Neil07]

Sounds like fuel injector "tick". It is normal. Do a search on You Tube you can find videos of many cars with the same noise.

[zummrox]

Originally Posted by Neil07

Sounds like fuel injector "tick". It is normal. Do a search on You Tube you can find videos of many cars with the same noise.

I was more referring to the first 60 seconds or so of the coldstart - there this loud metallic rattle which seems to go away once the engine slightly warms up. Sounds like absolute crap (to any bystander - hard to hear inside the cabin) although the car runs perfectly fine.

[Troy27]

Originally Posted by zummrox

I was more referring to the first 60 seconds or so of the coldstart - there this loud metallic rattle which seems to go away once the engine slightly warms up. Sounds like absolute crap (to any bystander - hard to hear inside the cabin) although the car runs perfectly fine.

My car sounds pretty much the same on a cold start. It runs great and has never thrown any codes. It bothered me at first but now I'm not worried about it.