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From digest.v6.n887 Wed Jul 16 16:11:08 1997
From: Don Eilenberger <>
Date: Tue, 15 Jul 1997 21:53:21 -0400
Subject: RE: m30 Spark plug gap and injector seals

At 08:43 PM 7/15/97 -0500, Douglas L. Donsbach wrote:

>Don Eilenberger <> wrote:
>> As far as seating the injector seals - and also getting them to last
>> FOREVER - I've used silicone vacuum (or stopcock) grease for years..
>> this is an excellent rubber lubricant and more importantly - anti-oxidant
>> (for those of you living in ozone heavy areas - like Southern CA)..
>The only problem with this solution is that silicone sealants are usually
>the death of O2 sensors and unless the sealant you are using says it is
>O2 sensor safe you are likely to accelerate failure of that component.

Doug - if you read the post carefully - note - I said it should only be rubbed into the rubber, not slathered all over the seal.. and FWIW - the silicone vacuum grease is non-outgassing, ie - it is made for use on O rings in a high-vacuum environment - much higher vacuum than your car engine could ever hope to achieve. Any outgassing in the high-vacuum environments it is used in would cause instant contamination of the systems - a much bigger problem than a fouled O2 sensor.

You also will note that I said *NOTHING* about a sealant - what I mentioned was a silicone based vacuum GREASE.

The problems that have been reported have been with silicone sealants being used - and they are entirely different beasties than a high-vacuum silicone grease. They WILL out-gas - it's part of their curing process. The gases given out could coat the O2 sensor rendering it senseless..

Do what you may - I've used the Dow-Corning Vacuum Grease on injector seals many times with no problem at all - but of course YMMV (and it probably will).

Please READ the posting before firing off the hip (although I have once in a great while done the same thing..)

Don Eilenberger
Spring Lk Hts, NJ, USA
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