406 Catalitic Converter
  • Register
  • Help
Results 1 to 5 of 5
  1. #1
    Member
    Join Date
    Jun 2012
    Location
    Port Macquarie
    Posts
    56

    Default 406 Catalitic Converter

    Can anyone tell me what is wrong with my Catalitic Converter as it is progressively getting noisier, as if there is a hole in the system.
    When I block the exhaust pipe there is good strong pressure and I can hear/find no leaks.
    The converter was renewed 5 years ago.
    When the engine has warmed to about 55/60 degrees the noise nearly disappears but when I accelerate it sounds like a hot-rod.
    Any help someone!!

    Advertisement

  2. #2
    Fellow Frogger!
    Join Date
    Dec 2012
    Location
    Melbourne
    Posts
    187

    Default

    Are you sure your cat is still in one piece?

    My 306 had a completely shattered cat for ages and a real nice growl from 2000 rpm to 2500 rpm. Different exhaust length on a 406 might cause different resonance.

    Then i got it fixed and it was dead quiet. Almost wish i hadn't fixed it after!

  3. #3
    Member
    Join Date
    Jun 2012
    Location
    Port Macquarie
    Posts
    56

    Default

    Thanks, what did they fix, any idea??
    I got under the car and had my wife start the car from cold (when it is the noisiest) I checked for leaks , none, but when I grabbed the Cat to move around under the car the noise diminished slightly and I could feel it vibrating.
    Check the last time it was replaced; 2010, 4 years.
    Guess I'll have to take it to the Exhaust shop.

  4. #4
    Fellow Frogger!
    Join Date
    Dec 2012
    Location
    Melbourne
    Posts
    187

    Default

    To be honest I'm not sure if the section with cat in it was replaced or cut and welded back up with new cat element inside.

    To diagnose the broken cat I tapped it with a screwdriver and could hear fragments moving around.
    Last edited by Bernie_K; 16th October 2014 at 06:04 PM. Reason: Mis-spelt word

  5. #5
    Fellow Frogger!
    Join Date
    Mar 2011
    Location
    Melbourne
    Posts
    413

    Default

    Picture a bunch of rocks rattling around in a vibrating tin can. That's what my cat sounded like when it started to fail, and was worse when the car was cold. The other symptom I had was a thin white 'smoke' from the exhaust when the engine was under load, which I only noticed by chance. Wasn't actually smoke but ceramic dust being blown out of the cat down through the exhaust.
    2000 306 GTi6 'Josie'

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •