Charlie, If you do get a replacement AUX FAN, they may at first operate backwards. Evidently there was a running change during the 96 model year. Its a very easy fix, you just unsnap the connector on the fan pigtail and reverse the wires and snap back together. Also, just so you know, these temp guages are plateau type, meaning the get up to about 95 and stay there unless the temp exceeds 110 ( I think thats the cutoff) then the temp guage will begin to move higher. Aside from the AUX fans, make sure your fan clutch is working properly. Once the temp exceeds 94, your fan clutch should engage and you will hear it roar as you raise the rpms. I am chasing a similar problem, my 1997 operates at 96-105 when I am commuting home, in stop and go traffic, a few hills with ambient temp 85 degrees plus.etc. I have replaced fan clutch, aux fans, thermostat. I will check once in awhile, while driving the temp via CCA. (hold rest button down for 10 seconds then toggle to 6 using the drivers side AUTO button). I think that even in heavy traffic, it shouldnt go above 96 or 97 , my next step is to clean the fins on the radiator, I havent done that yet, and with 280,000 miles I am sure there is a bit of gunk in there. Good luck and keep us posted.

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Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD