EdJennings

I have an 03 C240 that I bought new in 2003. It now has a bit over 73K miles on it. I was my wife’s car for many years, and got driven very sparingly. It ended up sitting for 2-3 years, a few years back. When I retired, I started driving the car for my everyday driver, and I put a few thousand miles on it in a year. Anyway, when I started driving it the ac was dead. I charged it with a couple of cans of 134a using a rig that attached to the low pressure side. I thought I might have to locate the low pressure switch for the compressor, but it must have had enough Freon in it to make the switch up. That was 4-5 years ago. The charge has dropped to the point that while the system still puts out cold air, it isn’t as cold as lt should be, or used to be. Get a reading of 55°F at the discharge. The low side pressure is reading about 25 lb. and it should be at least 35 and 40 would be better.
here’s the problem: I hook up to the low pressure service port and turn on the engine, and set the temp to max low. It blows cold air, so the compressor has to be running. When I activate the full valve on the gauge(trigger) the pressure drops but there is no flow from the Freon can. I’ve tried two different cans and two different gauge sets. One regulation, professional style set, and one of the type that you buy with a can at the auto parts store. For some reason, I can’t get any Freon into the system. Is there something I’m overlooking? I don’t need anyone to tell me I have a leak. If it takes several years to leak down just a bit, it’s more of a seep. Anyway, your input is solicited.

KevinH2000

I have had my AC system recharged twice in the last two years by my mechanic. Although I obviously have a leak, my mechanic suggested that attempting to repair it could become costly. His experience has been that the components in a 20-year-old car can be fragile, and I may end with a cascading series of repairs.

I was considering topping off the system myself in the future until I found this video:
That video and some other information I found suggest that it is best to have the system evacuated before adding refrigerant. I know that refrigerant recharge kits are commonly available, and that people use them with some success. I am not an expert on AC systems, but it seems possible that you are having the problem you describe because your system has air or moisture in it that is preventing you from adding more refrigerant.


I will be watching your thread to see if anyone else has suggestions. I would like to have my system repaired, but I have found that ignoring the guidance of my mechanic is usually unwise.

EdJennings

Thanks for your input.

112233

The information in the first video is not precise, e.g. there are cans without oil available and you lose refrigerant also through the rubber hoses not only by leaks and there is a drier integrated in the system so water will be absorbed.

C230 Sport Coup

Borrow the guages and vaccum pump from
Oreily. I did mine in the winter so my defrost would work
and I had to warm the freon can in pot of hot water to get the pressure up.
THEN it finally kicked in a sucked in the Freon.

112233

FYI: People in Europe are not allowed to buy real R134a, DIY refill only with R600a/R290 mixture possible.

KevinH2000

[QUOTE=C230 Sport Coup;9013005]Borrow the gauges and vacuum pump from
Oreily. /QUOTE]

I will check to see whether my local O'Reilly's lends this equipment to the DIY crowd. Thanks for the tip.