the Audi S4 Owners' Resource  

mike01s4's Step by Step Audi S4 Downpipes Removal Instructions:
by Mike Shimon (VAST Performance)

One of the best tips...cover all the little places in the engine where parts could fall into...also...ESPECIALLY the bellhousing behind the's got big holes in cover them up with duct tape or something.

(note: not every tool listed will necessarily be required)

  • 3/8" drive ratchet, short handle
  • 3/8" drive ratchet, 6" handle, tilt head
  • 1/2" drive ratchet
  • 1/4" universal swivel joint
  • 3/8" universal swivel joint
  • 1/2" universal swivel joint
  • 5mm allen wrench
  • 6mm allen wrench
  • 5mm socketed allen
  • 6mm socketed allen
  • 1/2" drive O2 sensor socket (deep 22mm with a slotted side)
  • 1.5' to 2' of 1/2" drive extension for the 02 sensorsocket
  • 3/8" drive extensions (6",3")
  • 1/4" drive extension (6")
  • 17mm short handle, 12-point box wrench
  • 17mm universal joint socket
  • 22mm box wrench
  • 10mm box wrench
  • 7 - 13mm sockets, 1/4" drive
  • Phillips screwdrivers
  • Flat head screwdrivers


  • disconnect battery ground
  • remove all engine covers
  • remove air box inlet tubing
  • remove air box
  • remove flex tubing to y-pipe
  • remove y-pipe
  • put coolant reservoir tank out of the way (disconnect lower sensor)
  • remove outlet hoses from y-pipe
  • remove the turbo inlet pipes, and be careful when removing the wiring harness retainer clips
  • plug all intake holes with some rags
  • on the intermediate firewall behind each cylinder bank, remove the wiring harnesses, brackets and open connections
  • jack front end of vehicle at least a foot into the air
  • use good jackstands and place them so they do not get in the way of the dp removal, i.e...the rear circular aluminum mounts (be careful not to crush them)
  • also jack up the rear and place on jackstands
  • remove the allen head bolts for the dp heat shields
  • make sure the 1st O2 sensors are disconnected, then remove
  • remove the passenger side exhaust gas temperature sensor (17mm), be sure not to ruin the head
  • remove any 17mm dp flange nuts that you can from up top
  • remove the shields above each inner cv joint on the driveshafts -remove any leftover 17mm dp flange nuts
  • remove the 2nd O2 sensors
  • completely remove the dp pipe support brackets where each dp starts to bend
  • disconnect rearward exhaust parts, do not leave the exhaust sleeve clamps attached to the dp's
  • remove the heatshield clamps
  • remove the heatshields and try to get the dp's out without the flange scraping everything

    this is the best part:

  • for the 2nd O2 sensors, you have two options:
    1. you can splice in about 8" of new wire, then heat shrink it all up to extend them

    2. you can cut all the wore harness clips above the drivetrain, and pull the sensors towards the rear while maintaining the sheath over the wires.
    (on my car, I did #1 because I had the equipment to do it, and I didn't want to remove the stock placement)...i've also done # 2 before, but it's a bit of a pain removing one of the nylon need a long screwdriver in there and just need to twist it so it breaks

  • be sure to put some anti-seize on the 02 sensor threads and dp flange studs

  • if you really want to be perfect...replace the 8 17mm nylon lock dp flange nuts and the dp flange gaskets

  • get everything loosely fitted, and the heatshields located properly, but not screwed in or tightened down whatsoever...then start tightening the flange nuts


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