In a message dated 10/29/98 5:00:47 PM Mountain Standard Time,
kdlewis@juno.com writes:

>
>  A word of warning: Silicone is (supposedly) extremely hazardous to the
>  health of the O2 sensor.  It will irreversible contaminate it.  I too like
>  the way it shines up rubber but have stopped using the spray version for
>  this reason. I found a product by Dow Corning called "4 Compound "; in a
>  tube, I use if a treatment is required.
>  Drive Safely & Good Luck
>  Ken Lewis<Kernersville,NC>86 VW crewcab;60 T-5 Coupe
>

True enough on the silicone poisoning of O2 sensor issue.  Tough for silicone
spray used externally in the engine bay to end up in the combustion process
though, I would think.  The concerns about silicone poisoning of the O2 sensor
surfaced years ago with the advent of silicone sealants like the famous
Permatex Blue Goo RTV which would presumably outgas when it got hot during
engine operation.  There are of course now sensor safe RTV sealants available
for use on or as exhaust manifold gaskets.

Silicone spray for aging cars is like penicillin was to disease prone humans
50 years ago, seems to cure just about everything!  I spray it on everything
whether it needs it or not.

Regards,

Carl