From digest.v7.n520 Fri Oct 31 15:08:38 1997
From: "Steve D'Gerolamo" <steved3_at_idt.net>
Date: Fri, 31 Oct 1997 10:28:20 -0500
Subject: Microfilters

The A/C microfilter is an important service item on most late model BMW's. The dealers generally replace at the Inspection 2 service. Replacement takes about 15-30 minutes on the E32/E34/E36 models and only a few minutes on the E38/E39 cars.
I just received an aftermarket microfilter element from one of my suppliers, an all white unit with the 3M and Purolator names on the side (I'm not sure who actually manufactured the part). These filters do not appear to have the same density as the factory parts...there are only 29 paper folds on the E36 aftermarket filter vs 63 on the factory part. The paper itself is more fibrous (similar in appearance to some of the cheap aftermarket air filters) whereas the factory element paper is smooth. The price differential between the 2 filters is about $1.50. I will continue to recommend and sell the factory elements only. SD