Hi I have a 2001 audi a4 1.8T quattro with only 175,000 kms, I'm expieriencing a loud knocking in my engine near the top, only when I idol. Just recently its been happening while I'm driving, I've performed a sieries of hot oil flushes and heavy duty engine cleaners and they have done nothing. I've been told to use "lucas" oil but have not gotten to that yet. If anyone knows the true nature of the issue please send me some feedback. Thank you,

 

located in socal by any chance? wanna video the car making the noise and post it up?

....other than that..take off the vavle cover and make an inspection...

 

I'm not I'm located in alberta, canada. And I'm not sure if I'm ready to go that far to take the valve cover off but if I can't find any other solutions then maybe that's what ill have to do...