///Mike@Boston Audi

I was adjusting my headlight with the engine running today and heard a very wierd noise that I've never heard before. It was a dull tapping sound, almost like a sawing machine. Seemed to be constant in frequency, but would sometimes go away for a period of time, then come back. Kind of like: tap tap ... tap tap nothing nothing ... nothing tap tap tap etc. It didn't sound metalic, high frequency - it was more of a dull type of tap/clap sound, kind of like if a part of the belt sheared off and was hitting something. It also seemed to be coming from the back of the engine bay, near the firewall. Any idea what could this be? It was pretty loud - very easily noticed by me when it first started happening. If it helps, this happened shortly after startup, with a cold engine.

AdamD

had this tapping noise at idle and after searching for answers, apparently the 5 valves per cylinder make that noise. I don't think I have really focused on my S for that sound but may just be that.

///Mike@Boston Audi

then go away for a minute, repeating. It's also a sound I've never heard before and was loud enough to be heard over the regular engine chatter.

AdamD

over idle pretty much. No idea past that.

ryans4

are you running a Ow30/0w40 oil?

I had this all the time running 0w30 oil, and it promptly got me to switch to a 5w30.

///Mike@Boston Audi

Yup, 0w30. Any reason why it's intermitten?

ryans4

...from my understanding, the lifters operate with a fluid "jacket" (for lack of a better term), if this jacket is thin, or not there, you get the tapping/ticking sound.

Usually if the car has been sitting, the fluid might have drained out, and upon start up, didn't get "worked" around the lifter yet.

This is speculation however, as I've not torn down a 2.7 engine to see exactly how it operates, but this would lead to the intermittent aspect.

Of course, if it doesn't get noticeably better once the engine is warmed up, your best bet is to switch to a 5w30 oil.

If that doesn't take care of it, you may actually have a problem with one of the lifters (though I really doubt it as this hasn't turned up on any S4's or 2.8 30valve A4's ((that i've heard of anyways))).

Try the oil switch (to 5w30) on your next interval and see if you still notice the ticking/tapping before you start worrying it's something else.

Kenneth Dalgliesh

Hi just wondering if you found the cause of the problem . I have exactly the same thing happening with my 2011 S4 with 96,000 miles on the clock . It disappears when the engine has run for 5 minutes