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Old 06-04-2012, 09:28 PM
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Join Date: Dec 2007
Posts: 5,055
A/C High Side fitting/Low side fitting location?

The A/C on the 1984 300DT stopped working. I noticed green colored fluid around the hose fitting on the hose fitting coming from the receiver dryer going to the expansion valve. I thought perhaps all the R12 had leaked out so I went to replace the hose and disconnect it from the expansion valve. as soon as I turned the wrench, refrigerant began to leak out under pressure! So....I quickly re-tightened the fitting.

Now, I want to hook up a Manifold gauge set to check pressures to see if the R12 is still holding pressure or if the receiver dryer hose failed or possible compressor failure. Question: Where is the high side fitting located and where is the low side fitting located on a 1984 300DT?
1991 560SEL, 1984 300DT
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Old 06-04-2012, 09:46 PM
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Join Date: Mar 2006
Location: Mount Holly, NC
Posts: 26,287
behind the alternator on the passenger's side of the engine... right in front of the turbo...
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!
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Old 06-04-2012, 10:48 PM
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Posts: 5,055
OK, bled the hoses per the manifold gauge set instructions. revved the engine slightly and got 240 on the high side, 90 on the low side. when revving the engine, the A/C compressor sounded like it was throwing ball bearings around inside; it sounded like it was about to explode! It is an Advance Auto made in china model so I'm thinking this points to a compressor failure? who makes a high quality compressor?
1991 560SEL, 1984 300DT
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Old 06-04-2012, 11:15 PM
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diesel enthusiast
Join Date: Jan 2007
Location: Germantown, TN
Posts: 5,437
this website

I ordered one from Phil last week. Here are the results:
How did this get in my garage?

Can you say 40.7F at the center vent in a 240D? Now, granted, it was only 73F that day.

If you have 90PSI on the low side.....doesn't that mean your expansion valve needs to be replaced?
Germantown, TN

Current Car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more
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