08-09-2001, 05:34 PM
A couple of days ago, my 96 A6Q started emitting a rattling sound from somewhere in the engine area.
It happens only when accelerating -- harder you accelerate, the louder the noise. I think the noise disappears (or gets drowned out) above 4000 RPM.
It happens only when the car is being driven (does not happen in Neutral or Park). This makes it very hard to diagnose.
Anybody had this before? I spent a good 3 hours at the shop without any luck. They looked everywhere -- couldn't find anything loose...
Mighty grateful for any advise on how to diagnose this.
08-09-2001, 07:53 PM
They did get the car up on the lift and looked around. Everything seemed solid -- no loose nuts/bolts.
Do you mean that the cats could be internally damaged? Car's emissions are fine, but it does consume oil (1 quart every thousand miles).
08-09-2001, 09:04 PM
Any idea on much I am looking at? I know there is a 8 year warranty, but like to know how much I'll spend in worst case scenario...
08-09-2001, 09:12 PM
<ul><li><a href="http://www.discountconverter.com/converters/audi/audi_direct_fit.cfm">Audi Cats</a></li></ul>
08-10-2001, 04:03 AM
Dealer list is near $1,000 each, plus about $500 each labor to install, making it a $3,000 repair at a dealer to do both. You can get them for about $335 from GPR parts. Some people have done conversions with exhaust shops, to use only one cat, or use non-Audi cats that will "fit" under there without comprimising ground clearance. In that case, you could get off replacing both with one or two units for $250-$500.
FWIW, I heard from my mechanic that VW/Audi exhaust parts now carry a lifetime warranty. This warranty was put in place so people wouldn't buy aftermarket systems, which in cases genuinely mess up the O2 sensors and cause all kinds of error codes... depending on the system and what all it does.
Best of luck...
08-10-2001, 10:19 AM
having the same problem right now on my '98 A6 wagon...also have had it on the hoist and cannot figure it out...sound is not coming from the cats though...coming from the inner CV joint area, but doesn't make much sense, cause it doesn't sound like a CV joint going bad....let me know if it is the Cats on yours, cause I'm not going to do anything else until it get worse....
08-13-2001, 01:32 PM
A local shop did it for $80. The car has a deeper tone and is a bit louder, but it feels much more powerfull. The state I live in does not inspect emisions, so that is not a problem. I suggest replacing the O2 sensors, which cause the Catlytic converter to go bad when they fail. You also want to fix the problem ASAP as chuncks of your cataltyic can work their way back to the mufflers. Good luck.