It's always difficult to diagnose problems with a modified system. Did the a/c work before you boogered with it? What does the person who charged you $1600 have to say about it? R134a is not as efficient a refrigerant as the original R12. If you are getting no cooling at all, the climate control system may not be turning on the compressor's electric clutch. The '85 300SD has the same system as the 300D, which includes a "Klima" relay to trigger the clutch. Klima has several inputs and all must be satisfied or the clutch does not engage. Search this forum for "Klima" and you can spend the weekend reading.

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970