Dumb question... Where do I add refrigerant? - PeachParts Mercedes-Benz Forum

derburger · #1 03-21-2007, 07:31 PM

My A/C compressor kicks on and blows warm air. Being an automobile noob, I do not know where the low side of the A/C system is to add refrigerant. I'm thinking the nozzle circled in the picture is the place to add refrigerant. The car was converted to r-134a

. It probably needs compressor oil as well, but I'm not sure how to do that, and the r4 compressor is 6 years old, most likely will need a new one soon.

Is this the low side of the A/C system, where freon(r134a) is added? Also, to charge the system, you open the can of freon into the system, and turn the A/C on high? I don't have a Haynes manual for this car yet, that's why I'm asking here. Thanks

Sbean · #2 03-21-2007, 07:34 PM

That's the place.

Matt L · #3 03-21-2007, 08:15 PM

Slowly open the valve. Do not exceed 40psi while charging.

vstech · #4 03-21-2007, 08:43 PM

and that is the dreaded R134 retrofit connector.
you will not be happy with the cooling from it.
John

Cervan · #5 03-21-2007, 08:48 PM

please if you ever empty your dreaded r134a please use r420a you will be much happier and its about half the cost of r12. but it cools just as well. it is also .02% oil so it helps lubricate and quiet down things in the system!

http://www.rmsgas.com/choicer420achillerconversion.htm

(PS ive had this refrigerant in my 1981 240d for about a year now NO PROBLEMS WHATSOEVER. in fact its at about 31 degrees at the vent IN 100 DEGREE HEAT! i live in california and i used it going over the grapevine jesus it gets cold)

oh yeah i forgot to remind you that when yo uare charging your r134a system dont turn the can upside down yo uwill charge the system with liquid refrigerant and that line goes directly into the compressor and if liquid refrigerant goes in there it will cause problems like siezed compressor..... liquid refrigerant will also pump the oil out of the compressor causing it to not have any oil.

tangofox007 · #6 03-21-2007, 08:53 PM

If you don't know what you are doing, the best place to add refrigerant is in the hospital parking lot. Get as close to the ER as you can.

Cervan · #7 03-21-2007, 08:55 PM

i suupose you could do it on a hospital bed lol.

derburger · #8 03-21-2007, 09:22 PM

Cool, I'll put the can in hot or ice water to make it add faster! (just kidding!) I had an interesting conversation about freon-related mishaps with an Autozone parts guy when he added r134a to my dad's car. He said he knew someone that died from putting the can in hot or cold water and adding it to the system

. I'll have someone else add it so I don't blow my face/arm/whatever off.

Matt L · #9 03-21-2007, 09:54 PM

Don't think you're so off-base. It will be necessary to warm the can unless you like waiting quite some time for the air to warm it.

Warming the can increases the chance of over pressurizing the low-side line. But you shouldn't be adding anything without gauges.

#10 03-21-2007, 11:21 PM

DO NOT USE CANS TO FILL THE A/C. They call them "death kits" for a reason. If you put too much freon in there it can build too much pressure and burst a hose or the can.

Take it to a qualified shop that has the right equipment. Have the system evacuated, vacuum tested, and refilled with the correct amount of oil/freon with a tracer dye.

Cervan · #11 03-22-2007, 01:56 AM

i belive the sightglass is a good method i dont see the need of gauges. unless of course you cant see through your sight glass then defintily get gauges.