Engine Knock Cold Start My07 WRX 46000 miles

[RyansMY07Scooby]

Hi guys, I have an unhealthy noise being generated on cold starts. The engine sounds like it is knocking. After around 10 seconds the knocking will start and will continue for around 3-4 minutes until the engine is warm. Could this be a belt tensioner?

The knocking rate matches the engine speed. So when the idle speeds drops the knocking slows down. The car was serviced 2 months ago and has plenty of oil. Has just done 46000 miles also. It is a My07 WRX.

Here is a link to my video

Thanks

Ryan

[Buggyeye]

sounds like something internal. maybe cam bearings? my speakers are naff so hard to tell

[Sandals]

Sounds like the noise is a lot slower than the actual engine speed... so I don't think it's knocking. Does sound like a bearing of some description...

[Mark D]

Sounds like an engine running with a washing machine in the background :/ check spark plug condition and colour, take them out, remember which came from where and take a pic of each.

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[Piggysniffer]

I can't even hear a knock ?

[quit]

it's a 2.5 .... sorry it's fudged 

[Tidgy]

what does the sound do if you rev it lightly?