Are there any a/c compressor alternatives to that famous and cursed R4?(W126 1981-1985)? I wonder if one of those Seltec or Unica A6 styles could work? They make one with a two groove pulley clutch for regular belts. I know I would need a different mounting bracket/manifold hose/condenser-how about a bracket/hose/condesner off a 1986-87 300SDL? (inline 6 same as inline 5?)

Ackits has the universal Seltecs/Unicas for less than $200; they offer; heavy duty-quiet operation, long life-integrated oil sump. The one on my 1993 W124 is a workhorse!

R4 problems;

1) Bad oil circulation-the R4s I have been through (5) the stamped X (between the clutch and the compressor body-marks the oil dispersement hole) is on the bottom near the ports and gravity keeps the oil from circulating to other areas and shortens compressor life.

2) New R4s suction/discarge GM style washer seal issues; hello jimmyL crushing a/c developement!, tangofox...many others, I read the many forum searches on this topic; My car, the manifold hose has an insert on the discharge, flat on the suction, manifold block is straight across, not warped; I have tried; green discharge, red suction (jimmyL W123) was slanted-terrible hissing leak, next green discharge, yellow suction (no insert) leaked, last month; green discharge, yellow suction with my homemade copper insert jb welded and tapped, leaked. I tried installing washers/seals with cfc nylog and another time dry, made no difference still leaked both times.

My new R4 (GM style seal washers) purchased 4-3-6 from Ackits (actually made/rebuilt? by B & T Champion Parts, Inc. Port Richie, Florida) $298 running on R12 and Castrol 500 visc mineral oil is now toast after 6 months.

3. Rebuilt R4s (hey at least you get the o-ring suction/discharge) Here is what I have gone through in the last 6 years all using R134A (before I knew better); GM Harrison, Four Season, Factory Air, Apco. All lasted about a season.

So now I am again planning on my anual spring time W126 a/c project. Is the A6 style Seltec universal compressor possible? If not I will probalby go with a rebuilt Behr R4 ($148) with the o-ring ports, R12, mineral oil, the usual flush-this time I am going to drill out one of my many used expansion valves. new rec/dryer, new expansion valve, rebuilt a/c hose....possible condenser, my electrical switches are 6 months old, so probably ok.

Sorry for the long post, had to inform/vent/seek advice!
Thanks

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1993 Mercedes Benz 300D 2.5 205K (ex wife's)
1984 Mercedes Benz 300SD 320K (SOLD)
2004 Mercedes Benz C240 75K
1995 GMC Sierra 2WD 5.7L 188K
1983 Mercedes Benz 300SD 239K (SOLD)
1987 BMW 325i 220K (SOLD FOR SALVAGE)

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