AC Problems with 96 C280
 

Hi,

Having AC problems, very weak cooling. Compressor clutch ativates and compressor turns. No strange sounds.

Have gauges and may need to pump down system and recharge to check for leaks.

Anyone know how much R134a the system holds and where are the hi side and low side connectors on this car.

Also if anyone knows the appoximate high and low side pressures it would be great.


Thanks

You don't need to evacuate to check for leaks, just put some UV dye in the existing charge since the compressor is still kicking in. Then use a UV light after a day or so to look for leaks. If you find no leaks at a connection, look at the condensation drain water with the UV lamp. If there is UV in the water, the problem is the evaporator.

High side connection is somewhere in line around filter drier. Low side is somewhere in line between compressor and evaporator.

It would be best to do some reading for safety sake. Without a/c understanding you can hurt yourself or your car.

Good luck,

Thanks Larry,

I fully agree with your caution, persons must be very careful while the gauges are connected to the high side. If the high side is opened while adding refrigerant the can may explode!

I am familar with AC systems and have done all the AC work on my Rolls and my other cars for many years. This is the first time I have had problems with the Mercedes AC system.

I want to evacuate the system and see if the system holds vacuum then add the prescribed amount of refrigerant before extensive dye leak testing. The proplem may simply be a loss of 1 once per year.

I found a placard that the system uses 1.9 lb of refrigerant.
I can find the low side fitting but I still have not found the high side fitting in the engine compartment. Could it be under the car?

I am trying to get the pressures. Is the standard 2.2 X F ambient rule for the high side applicable to this car?

Many Thanks