W210 air con help required

[robs-mbz]

The air conditioning on my W210 has never worked, I put it down to there being zero pressure in the system. This morning I bought one of the Halfords refill/sealer cans, charged up the system to 2.2 bar (27psi), the clutch on the compressor still won't pull in, fuses 4 and 7 in the fuse box are ok, I have pressure at the bleed screw right next to the pressure sensor, my hope is that its just the pressure sensor that is faulty. Are there any checks I can do to test that the sensor is working? My first thought was to short out the connections to the sensor to see if I could get the clutch to energise, so far I've resisted as I don't want to cause any more damage! Is the sensor a simple pressure switch or a pressure transducer, there are three wires connected.

Any help would be appreciated, please dont reply with "take it to a main agents or an Indy"

 

[robs-mbz]

Update from above:

I just rigged a temporary 12v supply to the compressor clutch, the pump now runs but still no cold air, interestingly, I measured the voltage at the disconnected cable, I get 8.7v, not enough to energise the clutch. What I thought was a bleed screw is referred to on the Russian site as a temp. sensor, there are no elecrical connections to it, is it some kind of thermo-mechanical valve? Also, the system took very little gas to get it up to pressure, I'm sure that the system is'nt full.

 

[television]

Hi rob, there is a sticky thread re the sensors on your car

 

[robs-mbz]

Spent more time checking out the air con, I'm sure the problem is that I just cant get enough gas into the system, the sticker under the bonnet says 2.2 bar (27psi +/- 0.7psi), it takes just a few seconds to get up to that pressure from empty, the contents of the can has hardly gone down, if I vent the system to atmosphere (very naughty I know!) the gas I put in has gone in seconds. Am I missing something? Could it be possible that there is a blockage somewhere?

 

[Ellsy Tanners]

Hi there,
I think you maybe miss understanding the values on ur sticker under the bonnet. These values refer to the amount of refrigerent the system should have in it. This is in grams or pounds/ounces. Typically about 800 grams for a a/c system. The pressure has no relevance when filling the system with refrigerent. If you manage to get that amount of gas in the system the compressor will be able to switch on.
The system is filled buy amount ( grams ) not pressure.
Hope this helps point you in the right direction

 

[robs-mbz]

Thanks for that, so the 2.2 refers to lbs weight? I cant get hardly any gas in there at all, the system pressure at the moment is zero, if I try to fill it I can get the pressure up to 45 psi on the gauge but it only takes a minute amount of gas to get there, its almost as if there is a blockage some where, whats the pressure switch calibrated to trip at?

 

[Ellsy Tanners]

In order to charge the system with refergrent the system needs to be vacumed out.
This alows the correct amount of gas to be put in and extracts moisture from your system.
As far as i know it wont be possibe to rechagre the system yourself without a aircon service machine.
where are you getting your pressure readings from? I dont know of any gauges on the car!

 

[Andy Wr]

All you are doing is putting refrigerant on top of air and moisture, you have lit the blue touch paper, now stand well back whilst your system goes into self destruct.

There are some self fill cans on the market with a gauge attached to them, oh we do laugh about them.

 

[nickbaker]

go to a good air con guy as the only way to sort out air con is with the correct kit i have done all sorts of quick fixes on mill kit in the gulf it works for a time but causes problems in the end the only way is the correct way (get some referances first )happy motoring