Look for my posts here on the site, and read my book, "Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning." I retrofitted a/c into my E9 20 years ago. There are a few things that makes it harder on an E9 than on, say, a 2002:
--If you want it to look stock, you need a console and faceplate from an original car (yes, Markos is 3D-printing the faceplates).
--You need the "intermediate piece" that sits between the evaporator assembly and the ductwork.
--You need the copper pipes that go through the firewall and right-angle-bend behind the glovebox. It's not like a 2002 where you can just run rubber hoses through. There's very little room back there. The early E12-based E24 also uses this kind of right-angle plumbing. Don't know if they're compatible, though. Certainly anyone who does copper work could bend one up, but I've never sourced it out.
The evaporator assembly is the same as a Bavaria, and the intermediate piece is similar enough to use.
If you can't find a rotted car that has these things (more difficult than it used to be), it's tough to put together a package that'll look correct in the interior. In the 2002 world, people do a variety of things, including using modern climate control boxes (heater core and evap core in the same box) and a console that's not original, but the more valuable E9s get, the more that approach is dicey. I drove mine for easily a decade with the original non-a/c console around the evaporator assembly, and no faceplate, as I couldn't find an a/c console and faceplate, at least not one I could afford.
The under-hood stuff (rotary-style compressor, big modern parallel flow condenser and fan) is all easy and like any other car.
--Rob Siegel
Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning [Siegel, Rob] on Amazon.com. *FREE* shipping on qualifying offers. Just Needs a Recharge: The Hack Mechanic Guide to Vintage Air Conditioning
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