Hello, I have an audi a3 1.6 tdi sport back on a 2012 plate. It's has covered just under 83000 miles. It's serviced every year when the mot is due.

About 2 weeks ago it started to developed a tapping noise which has got louder it also sound like it is running rough.

It is now in the Garage as mot and service are now due. The tapping sounds like it is coming from under the rocker cover. I have uploaded a video to YouTube which I will link below.

Thank you.

https://youtu.be/EvWz7FPcDBQ

Sounds a little like a timing chain (if you have one) and/or tensioner rattle. Your garage should advise you.

1 hour ago, cliffcoggin said:

Sounds a little like a timing chain (if you have one) and/or tensioner rattle. Your garage should advise you.

There first comment was that it was coming from to much air getting into the engine. 

1 hour ago, Lewis811 said:

There first comment was that it was coming from to much air getting into the engine. 

Really? So what specifically do they mean by that, and what do they propose to rectify the fault? It would help if you mentioned which engine and fuel you have.

3 minutes ago, cliffcoggin said:

Really? So what specifically do they mean by that, and what do they propose to rectify the fault? It would help if you mentioned which engine and fuel you have.

Oh sorry I thought I had. I have a 1.6 tdi. He said air was getting in through the oil filler cap. I had an injector replaced 2 months ago which failed. It was the  replaced again and that's when the noise first started. 

could  be  spring  on injector  if diesel  like    happend to  my nefu  and  me 

13 hours ago, Lewis811 said:

Oh sorry I thought I had. I have a 1.6 tdi. He said air was getting in through the oil filler cap. I had an injector replaced 2 months ago which failed. It was the  replaced again and that's when the noise first started. 

There is something wrong here Lewis. Either you misunderstood what he said or he is extracting the urine.

[1] An engine does not take in air through the oil filler cap. It might spay a bit of oil if the cap is missing, but it will not take in air and it will not make a noise.

[2] It is rare for an injector to fail, it is verging on the unbelievable for its new replacement to fail two months later unless there is an underlying cause that has not been rectified. Nevertheless if the engine is missing on one cylinder it would sound like yours.