O2 sensor wrench

Ed Kellock ekellock at gmail.com
Sun Nov 29 11:41:15 PST 2009

I recently changed the O2 sensor on the 90 V8.  It was pretty well welded in
place.  I had the luxury of not needing to drive the car for a couple of
days.  I soaked it with PB Blaster once a day for 2 or three days.  I also
used a punch and a hammer to give some impact treatment a couple of times.
On the V8, the sensor is in the middle of the crossover of the exhaust and
right down above the ground just forward of the trans pan and a bit back
from both front wheels so it has a lot of exposure to road grime etc.  I
finally got the sensor loose and then had to back it out little by little to
loosen the crud built up on the end of it inside the exhaust.  I would
backed it out sixth of a turn at a time, going back and forth (tighten,
loosen, tighten, loosen) to free it up before proceeding to avoid completely
stripping the threads.  I used the special split socket tool and a 22mm
closed end wrench (the connectors fit through the 22mm hole) to attack it


-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On
Behalf Of Ben Swann
Sent: Saturday, November 28, 2009 8:05 AM
To: hayesmyers at gmail.com
Cc: quattro at audifans.com
Subject: O2 sensor wrench

Most parts stores sell a slotted socket specifically for O2 sensor removal.
22 mm is the O2  size for stock sensor.  

Often these are so "welded" into place that you sometimes need to destroy
the old sensor getting it out, which is OK since you were replacing it.  You
may need to cut the wire at the sensor and hammer on a 21mm.  You may need
to knock the housing off, and in one case I had to drill out the center and
re-tap threads.  A tap for a lawnmower spark-plug will cut the correct

Hopefully yours is not this much of a PITA.


[Date: Fri, 27 Nov 2009 14:29:18 -0500
From: "Hayes Myers" <hayesmyers at gmail.com>
Subject: o2 sensor
To: <quattro at audifans.com>
Message-ID: <032b01ca6f97$ea899370$bf9cba50$@com>
Content-Type: text/plain;	charset="us-ascii"

Well..finally decided that o2 should be changed. (mine is 6+ years old I
think!).   Are
there multiple sizes of o2 wrenches? (crows foot type tool)? Anyone know
what size the I5 uses?  Yes. absolutely ridiculous question of the day.

Happy Friday and thanks!

Hayes Myers, P.Eng

91 200 TQM 10v
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