[V8] Replacing o2 sensor

[dsaad at icehouse.net]

Chris -
the sensor is quite likely to be rusted/fused in place if it has been
there for any length of time.  There are special sockets made for this -
but I just use a 7/8" box end wrench. (at least I think it is 7/8 - just
find a wrench that fits your new sensor) Do NOT use the open end of the
wrench or you risk rounding off the corners of the sensor - and then you
have a real mess.
The connectors easily fit through the box end so there is no need for the
fancy socket.

Use penetrating oil, and if the sensor is really stuck, try to slowly work
it out.  It is quite likely that some of the sensor threads will get torn
off and stuck in the bung (the threaded part of the exhaust pipe).  There
is a spark plug thread chaser tool you can use to clean the threads out if
you need to - but in a really bad case (like mine a few weeks ago) you may
need to carefully pick out the broken threads and or use a real tap to
clean the bung up.  Any auto parts store should have the right tap - it is
a spark plug thread.

In a really bad case (sadly again like mine a few weeks ago...) you might
find it easier to remove the section of pipe so you can work on it at a
workbench.

To reinstall, the new sensor should come with antiseize already on it.  If
not be sure to use some. Don't over tighten the sensor either.  It does
not need to be torqued down hard at all.  Less than 20 ft/lbs is plenty.

I don't know how the wires are routed on an automatic, but on a manual you
have to be sure to route the wire just like the factory did or it will
drag on the axle boot and that will ruin your day in the not so distant
future.

Dave


>
>  Hello tonight i changed the fuel filter on my 1990 v8. It was a pain in
> the ass but it's done. Im pretty sure it was a original filter which
> would make it over 20 years old. it was bright orange and had the Audi
> symbol on it. It was a audi part.
>
>  Tomorrow night i am most likely going to be changing my O2 sensor. It
> should arrive in mail tomorrow.
>  I don't know where it is, or whats involved. I've got a 1993 4.2 engine
> in my 1990 Audi. (i swapped out motors) So its not a 1990 engine.
>  I could use a little advice on which tools to have handy and a basic over
> view on how to do it if you fellows don't mind.  Thanks again  chris
>
>
> _______________________________________________
> Audifans V8 mailing list
> Send posts to: mailto:V8 at audifans.com
> Manage your list connection: http://www.audifans.com/mailman/listinfo/v8
>
> You can help keep the audifans site running by shopping at
> http://audifans.com/shop/
>
>