> I just replaced the oil filter on my 1984 Westy.  I noticed that the one
> I replaced it with had a different part number, even though they are
> both from Volkswagen.  The one that was on the bus had number 034 115
> 561A.  The new one had number 070 115 561.

> As I understand it, the letter denotes the latest revision i.e.
> the higher the letter, the later the revision

Yes, but it's the revised version of the wrong filter. The 070 is the
correct Vanagon filter; the 034 is a Rabbit/Golf filter.  Also, "revised"
does not always mean better; it can simply mean different.  For example,
when looking at two part numbers, if one part ends in A and one in B, the A
may fit earlier year applications of the model while B fits later years.

- Ron Salmon
  The Bus Depot, Inc.
  http://www.busdepot.com
  (215) 234-VWVW