Startup roar

[Kardell]

Hi All,
I hope you are doing well.
I have Audi A4 B6 1.8T 190 BEX.
I have noticed this kind of roar noise during startup.
I heard that it's due to the oil not being delivered properly at startup. However I also noticed that this noise is not only on cold start but also when the engine is still hot.
What is the culprit?
Please have a look:
https://tempclip.com/pHEP5I2dKOqIYT4/watch
https://streamable.com/8jhbm9
Best regards

[Turbo510]

I'd remove the serpentine belt and see it the noise is gone. If so, check everything turned by the belt for problems.

[fabric8]

Agreed. It sounds like the belt slips for a few seconds then catches. Could also be a bearing on one of the pulleys.

If you remove the serpentine belt, spin each of the pulleys you can by hand and feel for play or grittyness. Maybe the tensioner mught be going bad.

One other possible thing it could be is the SAI pump. My dad's EGR valve went bad causing condensation to build up and pool water in his SAI pump. At first start or when very cold starts, the SAI pump comes on and made a similar noise since it's bearings were rusted from the water. But after a few seconds, the noise would go away.

Sent from my SM-S908U using Tapatalk

[Kardell]

Gents, thank you for the insight