A3 Issue - Engine Noise

[Ed Miller]

Hi all,

I have a 2013 A3 saloon. I recently had a big turbo and engine issue so got my turbo reconditioned and a second hand engine put in a month ago and all was fine.

Recently I have started to hear a noise coming from under the bonnet, like a whining/humming noise, which never happened before the incident above. It happens when I start moving from stationary, lasts about 1 second then stops when I am >5mph - it doesnt seem to affect performance, but still doesnt sound right. It doesnt happen in neutral when I rev the engine, it doesnt happen all the time, and it happens more frequenctly after I have driven a stint at 50-70 mph. If I do a small trip around town it rarely happens. Which is inconvinient as when I took it to garage round the corner it didn't happen so they struggled to diagnose the problem.

I was wondering if anyone knew what it could be?



Please see link above to a video showing the noise, any help would be greatly appreciated. (I made sure there was noone & no cars around while taking the video so it was safe)

Thank you,
Ed

 

[Dadar]

That sounds like a dry bearing type noise to me either alternator or idler pulley for the auxiliary belt.
What engine do you have and have you had any other replacement parts installed apart from the engine and turbo that you have mentioned?
You can eliminate my first suggestion by removing the auxiliary belt and seeing if the noise persists.
Bear in mind that with the belt removed the alternator will not be charging the battery and the waterpump if applicable will not pump.
If you have a manual gearbox it could also be the clutch release bearing as it does seem to go away after you pull away.
Hope this enables you to track this down and fix

 

[Ed Miller]

Thank you that is very helpful.
It is a 1.4 TFSI, 138bhp. It is an automatic, so maybe that rules out the last possibility, although maybe there is an automatic equivilent.
No I dont think there were any other replacement parts other than spark plugs. The garage moved over the timing belt and some other auxiliaries from my old engine.
I will make those suggestions to the garage next time the sound gets bad.
Thanks again.