I have had my 99.5 a4 for over a year, and since the beginning I have heard this ticking...my mechanic says its nothing to worry about, but im just wondering if anyone knows what it is. It sounds like a rattlesnake is in the passenger side of the engine bay, but it only makes the sound when I accelerate. I can't hear it with the windows closed, and its only really noticeable when the windows are open and i'm driving alongside a barrier for the sound to bounce off of. Could this simply be the turbo spooling, or something worse?

 

Passenger side? Hmm. If you're lucky it'd be an exhaust thing. Could be the cat... throwing any codes?

 

i dont have the vag-com but the CEL was never on...this couldnt just be the turbo noise? I've also reaad alot about lifter noise. To say passenger side is a generalization, it just sounds louder on that side.

 

Hmm... well if it was exhaust then it's really nothing to worry about. Lifter noise is also a possibility, and it's true, you really can't worry about it too much, unless it gets very loud. Was your mechanic more specific, or did he just tell you not to worry?

 

does the ticking increase with speed??

 

ticking seems to stay the same no matter what speed, as long as the clutch is engaged and i am accelerating..as soon as i take my foot off the gas its stops

 

Could be a cracked exhaust manifold, All series one land rover Discoveries have that problem, as you drive you hear a very annoying tick and it only happens when you apply gas.. (more backpressure in the exhuast go figure.. )

 

I also have that sound on my 99.5 A4...
I think the sound is from the engine when the sping is open and closing the valut...it makes those kind of sound...
I saw ppl rebuilt muscle car on TV...when they tried to start the engine....it moves like piano when u click keys.....
and it makes the ticking sound...i think it's normal....
i'm not 100% sure....

 

If it doesn't change with rpm, then its not lifters.

Rattlesnake sounds like a going cat to me. Or possible a loose hanger or heat sheild or someting like that. Somewhere there is something loose. It doesn't vibrate at idle, just when there is more vibration from engine acceleration.

Have someone rev the engine while you try to pinpoint where the sound is coming from.

Personally, this would drive me nuts and I would have to find out what is going on!

 

cats can rattle, and then crack at the flange.. common problem.. or heatshields... could be rattling under load when you get on it.

I have a fluttering in my car right now... making me mad.. its only under boost.. im thinking its an exhaust leak.. but i have no real way to test.. i need some ideas...