The a/c compressor went out on my 95 E300D I have two used ones but I don't know if they are working or not is there a way to test them before I install it?

What makes you think it is the compressor?

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Garage:

2017 Chevy Colorado Diesel (nanny state emissions)
2005 Volvo S40 T5 AWD, 77k
1987 Mercedes-Benz 300D turbodiesel, 4 sp auto, 156k - 28.7 mpg
1996 Tracker 4x4, 2 door, 16v, 3 sp auto. 113k - 28.6 mpg

WARNING: this post may contain dangerous free thinking.

The compressor makes a lot noise when I turn on the a/c

If it really IS the compressor... as compared to the compressor clutch for instance.. stop running it.... you might save a lot of work in terms of a ' Black Death' sent downstream.....

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The answer to the original question is, "No".

Even though a compressor might spin freely by hand it is no indication of its internal condition. If it doesn't turn at all MIGHT be an indication but not definitive. Oil sitting for a long period can act as a temporary "glue" which might loosen.

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I think there is... which might be addressed in the MB AC manual .. but you or anyone else I know of do not have the bench equipment to test them and compare.... so practically....' no' ...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I once rigged up a pressure gauge to the output port of a used R4 compressor. I spun the compressor (after putting a little oil in it) with an electric drill to see if it was "compressing". I do not remember what the psi numbers were but it was "compressing". I never ended up using that compressor (still have it) so the "test" was for all for nothing.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Tanks guys for the replies I'm going to take a chance and install one of the used compressor that I have

When choosing. At least choose one that you can spin the clutch/belt pulley smoothly with no noise, and the clutch face should be able to rotate it without much force... a wrench should not be needed...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

I would do the following before committing to the install:
- spin the outer part of the pulley, it should be absolutely silky smooth
- spin the inner part of the pulley, it should have some minimal resistance but you should be able to easily move it back and forth with simple finger pressure and should again be smooth, no grinding, hesitation, or roughness
- apply 12 V to the coil, ensure the clutch engages and there is no slip between inner and outer hubs.

If it passes all this, now proceed to flushing the compressor with oil. Use PAG46 for R134a or mineral for R12. I would pass at least a full 8 oz bottle through using the drain port (the bolt adjacent to the electrical connector for the clutch (for Denso compressors - used on the 124 and later) and the suction and discharge ports. Rotate the compressor by hand to ensure the oil flows through everything and drain it thoroughly by holding it upside down over a drain pan and spinning the hub. Confirm the drained oil is clear - if it has debris in it, chances are the compressor has Black Death and it is toast.

If you get through that, fill the compressor with new oil to the proper charge quantity and install it.

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2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Tanks Vstech and jay bob I'll follow your instructions

Can't you swap the clutch much easier? You can leave the refrigerant in the system. The bearings inside the clutch take the main load and usually give such grinding noises first. You can even rebuild a clutch, if you have a shop press. Many use the same PN 2-row ball bearing, but it costs ~$25 and I often buy new clutches for less, so never tried.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

If I'm able to swap the clucth like you said it's going to save me time and money so I'm going to try that first tanks