I had the compressor blow a front seal on my '90 300E last year. I replaced the compressor and dryer assy, purged both directions with scuba air through the evap core. Pumped system down with vac pump and replaced oil, dye and R-12. Worked great for the 3 months of remaining summer (Phoenix) last year. Gauge readings were the same after 90 days as when new.

This year I have a little cooling, but not much. Gauges show 30 psi static on both gauges while off, a vacuum on the low side and about 70 psi on high side. Compressor clutch cycles on command. I can't find any red dye at fittings.

Any advice from the gurus? You guys have made Mercedes ownership possible. So good, in fact, that I just bought a '92 400E for the wife. Now I have 2 white W124's!