Ac ? 1983-380sel - PeachParts Mercedes-Benz Forum

jim16671836 · #1 09-10-2006, 08:59 PM

Behind the compressor right before the freon enters or leaves the compressor there is a tube about 5 inches long and a 1 1/4 inch in diameter... What is it for... Does it ever go bad or become plugged............ This is the Compressor series that Mercedes used before they started using the R4(GM) compressor.
Thanks for any help.... I have changed all the O-rings in the system, drained or blown all the oil that I could from the system..... installed a new dryer and expansion valve... vacuumed the system for hours at a time... the blower is working and air comes out the center vents and some from the lower side vents but none of it is cold... maybe cool at best... I have oil in the system and charged the system with 134... 85 percents of what the r12 was... ... I have went thru the sequence twice and still does not get cold...Jim

Johnhef · #2 09-10-2006, 09:21 PM

ok dumb question but didnt see mention of it so i have to ask, is the clutch engaging? what are your pressures?

jim16671836 · #3 09-10-2006, 09:54 PM

Yes the clutch is engaged because I jumpered it so that the freon would be easier to insert and I still have it jumpered.. When I get cold air I will check and see if the clutch will work from the switch.... Pressures are 35 and 275 Jim

Whiskeydan · #4 09-10-2006, 10:09 PM

Sounds like it may be over charged. What's the ambient air temp across the condensor?

jim16671836 · #5 09-10-2006, 10:27 PM

I have tried to be carefull and just put in 85 percent of the 2.2 pounds of R12 that the tag on the radiator calls for... about 33 ounces of 134... do you count the sealer, oil and dye as part of the total ounces??? How do I check the ambient temp accross the condenser???? What will that show me and what should it be... the aux. fan came on just like it should... Jim

Whiskeydan · #6 09-10-2006, 10:58 PM

It seemed to me like the pressures were high as if the ouside air pulled across the condensor was hot or it was over charged.
Now that I think about it. You may not be that far off. May have too much oil, sealer... in there.
What did you use to evacuate it with? You need to make sure you pull a decent vacuum to boil off the moisture.
What do the lines feel like? May have warm air blending.

jim16671836 · #7 09-10-2006, 11:10 PM

What is warm air blending????? I pulled a vacuum of about 26 inches and then I valved it off... I pulled the vacuum on both the low and the high side and then after I valved it off I let it set... I think I should have kept sucking the vacuum for 30 minutes or so and then shut the valves to check for leaks for a couple hours... Maybe this is where I messed up?????? hey I think everybody for helping me... Jim

Whiskeydan · #8 09-10-2006, 11:23 PM

Warm air blending in the ductwork. Thats why I ask what the refridgerant lines feel like.
The refridgeration system may be working fine, perhaps your just not getting the air solely across the evaporator from the vents.

jim16671836 · #9 09-10-2006, 11:53 PM

The low pressure hose is cool but not cold and the high pressure line is warm but not hot... should I vacumm for 20 to 30 minutes??????????? I will also check the ducts and see if the heater might be dumping hot air in with the cold..... Jim

david s poole · #10 09-11-2006, 10:56 AM

first of all 134 only about 70% as good as 12 in same system and it sounds as though heater valve is on so heat fighting cool.monovalve diaphram problems common so take pair of needle nose visegrips and close off heater hose and try again.sounds like you did everything else correctly.