I'm also looking for the original recovery tank for my 1990 345LE.
However in the meantime I'm using a universal one I found at a local auto parts for about $15 that is a bit smaller than the one elbundi is showing but I've had it in for probably a year and it works just fine, though smaller in volume.
Mine has a sweet aluminum tank, is that what yours came with? I don't think it's a GM part at all, I've seen similar tanks at Summit Racing Equipment dot com however. It's similar to the Be Cool 70058
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.