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Re: copper crush washer vs aluminum

-----Original Message-----
From: Craig D. Niederst <niederst@telerama.com>
To: quattro@coimbra.ans.net <quattro@coimbra.ans.net>
Date: Friday, April 24, 1998 6:04 PM
Subject: copper crush washer vs aluminum

>I finally got that damn drain plug out and went to the dealer (Day Audi)
>over lunch today and bought a new drain plug. I was issued an aluminum
>washer with the plug instead of copper. I questioned the parts manager, and
>he told me that this is what Audi has been sending them. He said he hasn't
>seen a copper washer in a couple of years. He said they only use these
>aluminum ones on the Audi's they service. I remember a while back that a
>lister mentioned aluminum washers were detrimental due to the metal types
>not being compatible (i.e. oil pan metal and aluminum). I have already
>installed the new washer, and changed the oil. Was this a mistake to use
>aluminum washer? TIA.
>'92 100S (71k)
>'92 100S (71k)

Hi Craig;

    They are still selling the copper washers here. I've never seen an
aluminium one.
    The problem you are referring to is galvanic corrosion between the steel
oil pan and plug and the aluminium washer. The aluminium will corrode
preferentially; the washer will dissappear at a rapid rate given the proper
conditions (hot - yes, electrolyte - not too likely unless you drive your
car on ocean beaches or Canadian winter roads). If you change the oil at the
recommended intervals (or sooner!) I doubt that you will have a problem in
any case.


Fred Munro
'91 200q  250k km