if you're opening up the AC system, there is a complete o-ring and seal kit at AutohauzAZ

If you can afford the downtime, after you've tested them open all the pods and examine the rubber bellows for fine cracks. Then order the replacements for what you need. I'm not sure if there are high use pods but those would be first on the replacement list.

After you've removed the dash, the next time is much faster if you've taken notes. I have a whole video I shot so I remember the details.

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'88 300TE, 175k, black RENNTech 3.6L Recaro C's AMG 1 SOLD
'92 500E, 110k, Spruce green, stock SOLD
'94 E320 Cabriolet, 130k, E500 wheels, Emerald green SOLD
'94 E320 Cabriolet, 110k, black, stock, SOLD
'88 300TE, 229k, dark grey, SOLD
'90 300CE, 212k, white, new paint, SOLD
'91 300E, 209k, white, rebuilt head SOLD
'74 914-6, grey, 2.7L 325hp twin turbo Audi conversion