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Cat failure on A6 2.8

Discussion in 'A6/S6/Allroad forum (C5 Chassis)' started by StuartL, Jun 4, 2007.

  1. StuartL
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    StuartL New Member

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    [Jun 4, 2007]
    I've got the A6 Avant Quattro 2.8V6 and the cat (or some similar exhaust component) has failed causing a rattling like noise at low revs. Local service place has just MOT'd it and it's passed the emissions so their recommendation is to leave it until the noise gets worse/annoying or the next MOT comes round. Obviously replacing the cat can be expensive.

    I've had a look around to see whether it's worth replacing the eight year old exhaust system with an after market system but I can't find a single off-the-shelf system for the A6 2.8. This leaves custom made units and their obvious cost overhead. Southampton Tyre Services (registered dealer for powerflow) have given me a finger in the air quote of 1-1.2k for a cat back system including the cats.

    So my question is:

    I live near Newbury, West Berkshire in the south of England. Are there any places locally worth visiting for a custom exhaust system? Is it worth replacing the stock pipes (which have a fair amount of surface corrosion but seem to be solid) or just replacing the cat?

    TIA,
    Stuart
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  3. yendall24
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    yendall24 Member

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    [Jun 4, 2007]
    hi mate i have just fitted a new cat to my a6 2.8 quattro avant today i bought it from sutton auto factors 01623 441331 delivered to my door for £89.05 all in .they are easy to fit its just 3 nuts on the down pipe unplug the lamda probe and loosen one clamp if you are fitting the nearside /passenger side undo the 3 screws holding the expansion tank move it to one side doing this will allow you to unplug the lamda plug and give you access to the top nut on the down pipe dont remove the lamda sensor until you have the cat off its much easier this way .refitting is a reversal of removal it took me about 45 mins to fit . as regards after market exhausts i have a cats back stainless powerflow system fitted it cost me £475 its quiet round town but when you put your foot down its worth every penny ps there is a steel gasket between the down pipe and the cat mine was in perfect condition so i re used it try and get one before you start just in case its kaputt any questions dont hesitate to ask
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  4. StuartL
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    StuartL New Member

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    [Jun 4, 2007]
    What caused you to replace your cat? Did you have a rattling/ticking/shaking like noise coming from the underside of the car like I do?
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  5. StuartL
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    StuartL New Member

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    [Jun 4, 2007]
    And... (oops) Is that £475 a twin exit system as per the standard exhaust? i.e. Is it a drop in replacement? Do you have any photos?

    Do you have any powerflow part numbers/designs/dimensions etc?

    Thanks :)
    Stuart
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  6. yendall24
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    yendall24 Member

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    [Jun 5, 2007]
    yes when you put your foot down it whistled like a scalded cat the ceramic core breaks down and shakes like a babies rattle. i dont have any pictures but basicaly it as 2 boxes per pipe centre and back i got them to cut the rear valance so you can see the outlets like the a4 1.8t i have 3 inch round stainless out lets it was fabricated from scratch . i had it done at district garage in bolton gtr manchester £475 all in and i am over the moon with it
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