75 Air Conditioning - Alfa repairer or specialist?

[alanm]

Hi all,

I HAD the rare privilege of Alfa 75 air conditioning that worked very well.
Returning from Winton a couple of weeks ago I was turning it off and on so that it didn't get too cold inside (seriously).
Anyway, I must have worn something out because the switch stopped clicking when rotated to about 11 o clock position and it stopped blowing out cold air
Instead I started getting a hissing sound from the vents.

I am guessing that the gizmo (pressure valve ?) behind the switch has failed, but I could of course be completely wrong about this.

My question is: should I take it to my friendly Alfa repairer or go to my almost as friendly air con guy?
Or, is going to be so expensive to fix that I should just by a towel to mop up the sweat?

Anyone had any experience with this problem?

Cheers,
Alan

[colcol]

Ok, is the fan still blowing air?, because if it stops blowing air, then the evaporator freezes up and it starts making clicking sounds, as it has got so cold, there is ice forming on the coils, but this sounds like its the thermostat switch, these have got a long thin tube that fits in the evaporator to sense the temperature, and it is filled with gas, the gas leaks out of the tube and the bi-metal switch stops working, when the evaporator gets warm, it switches on the compressor, when it gets too cold, it switches off the compressor to stop it freezing up, i have replaced several in the 33, not Alfa parts, but generic switch from Repco or Airconditioning supply place, if it is generic switch with Alfa switch knob on it, an airconditioning place would be ok, but i would take it to Alfa Romeo repair shop, as it might be an Alfa Romeo switch, not generic and they will have to know where to source and fit a replacment from, Colin.

[alanm]

Colin,

Thanks for your response, I decided to take the car to an air con specialist first.
Turns out my prognosis that the switch was the culprit was incorrect!

The problem was created because the thermo fan was not kicking in when the air con was switched on.
As a product of the fan not working, the pressure (or temperature?) in the system became too great, forcing some of the gas out through one of the seals.
As a result of this, the level of gas went below the critical level (and I believe this is a narrow margin) and the air con ceased to work properly.

Having been re-gassed the switch makes the clicking sound again (go figure). The air is ice cold.

Why did the thermo fan cease working causing the whole problem? Yours truely most probably knocked the terminal off a relay whilst fiddling with the distributor wires!!  Another lesson learned.

Not the car, but operator error!

Cheers,
Alan

[colcol]

Hello Alan, good to see the aircon is working again, next time you get the aircon serviced, you need to get them to put a new receivor drier, with a 2 way safety switch,  that is the black can at the front with 2 hoses at the top, [it is a bit bigger than a drink can], the 2 way switch cuts out the compressor if it runs out of gas, [low pressure] and cuts out the compressor if the fans fail to cool the condensor, [air conditioner radiator at the front], and the head pressures go up too much and blow out the seals, the head pressures can also go up too much if it becomes too hot, i beleive the switch is a E.P.A. requirment, or A.D.R. to stop the dangerous refrigerant gasses escaping into the atmosphere. The switch has a gas tube in it and when it gets hot it switches the compressor on, when it gets cold the gas contracts and switches the compressor off, if the evaporator gets hot due to lack of cooling, the switch stays on and doesn't click on and off and creates the impression that it isn't working, Colin.

[alanm]

Hi Colin,

That's very good advice, I will be going back to have the system serviced because I think they do a good job.
I will ask about a safety switch.

Hey Colin, thanks also for participating in the Driver Training day at Winton. Cooper and I really appreciate the time and effort that you, Ross Flood and the other guys contributed. You guys deserve medals. I intend to write a few words describing the event for the next issue of C&S.

Cheers,
Alan

[colcol]

Hello Alan, don't have the safety switch fitted, as they will have to fit a different receivor drier and dicharge the gas out of the system, just wait until you have to have it regassed and get it done then, do you know what sort of gas they use?, because yours would have come out with the old R12 gas, just like my 33 did, or has it been retrofitted to take the newer R134 gas, Colin.

[alanm]

Hi Colin,

System was re-gassed with 134A.

I bought the car in Brisbane more than a year ago and don't know anything about the air cons history.
The guy I bought it from was a commercial air conditioning specialist and he commented that I was going to love the air conditioning.
He said that his mate had 'worked on it' or words to that effect.

I have assumed since that some hoses, seals etc were replaced.

Cheers,
Alan