I have low cooling from my A/c (300CE R12). normally it is low in R12.
When I get the R12 filled, the first few days it is really cool.
Then it starts to get less cooler. My mechanic filled it with air at high pressure and left the car & the A/c running for two hours. no drop in pressure.
He believes the R12 leaks very slowly from the compressor & it would be better to replace the compressor.I would like to know the options.
The temperatures here are 47C now in the summer.
I have noticed that cooling is much beter in the toyota's & the Nissan's here in Dubai.
Will a compressor from these cars fit & will it give a better performance.
Too many questions as it keeps getting hotter.

__________________
300CE 1989 Euro Model.
ML350 2011.

You have a leak, question is, from where is the leak originating? Replacing the compressor as a stab in the dark to fix a leak is an expensive solution. My mechanic has a hand-held sniffer that can tell you where the leak is - absolutely without guessing. You need a mechanic who has the same sniffer. Then you can solve the problem once.

__________________
- Brian


1989 500SEL Euro
1966 250SE Cabriolet
1958 BMW Isetta 600

Don't you already have the same compressor as Toyotas and Nissans?

__________________
2012 E350
2006 Callaway SC560

Can your explain your statement;

My mechanic filled it with air at high pressure and left the car & the A/c running for two hours. no drop in pressure.

Sounds like he removed the freon and filled the system with high pressure air. If in fact he did that the oil circulation for the compressor was surely affected in a negative way.

Am I properly interpreting what you said?

__________________
I got too many cars!! Insurance eats me alive. Dave

78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k

Yeah dpetryk, you interpreted it correctly.

When he leaves it running for a couple of hours after filling it with air at high pressure, there is no drop in pressure. After that he again fills it with R12 & only after the car has been running for a couple of days there is low freon.
Also after researching for a few days I understand that the best bet to increase cooling is to increase the airflow over the condensor i:e to have a better fan, correct me if I am wrong. what is the best fan available that will fit right in.
I know lots of questions, but I am really sweating.

__________________
300CE 1989 Euro Model.
ML350 2011.

Does your car have one electric fan out front, or two?

__________________
2012 E350
2006 Callaway SC560

It has only one electric fan

__________________
300CE 1989 Euro Model.
ML350 2011.

STOP HAVING AIR PUMPED INTO THE SYSTEM. Pumping air into the system ruins the drier. Did you know that it is recommended to replace the drier each time the system is opened? That's because the drier gets exposed to the atmosphere and the dessicant quickly becomes saturated with moisture. Pumping air into the system is much much worse than just briefly opening it up to atmospheric humidity.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Good point on the air.

Nitrogen seems to be the choice of the professional.

__________________
2012 E350
2006 Callaway SC560

Here is a step-by-step method to test compressor cut-off. http://www.peachparts.com/shopforu...=158591&page=5

Note this is for a 87 diesel, so one value is different, but let us know what you find on the basic tests.

__________________
Saumil S. Patel

An update.

Replaced the compressor & the receiver drier.
The A/c has been blowing cold since then.
Hopefully it will stay like that for a long time.

__________________
300CE 1989 Euro Model.
ML350 2011.