84 911 AC erratic cooling

[Gabar]

Hello everyone,,,
Our 1984 911 was converted to 134 about 4 years ago. Recently had leaks in the system fixed and it seems to be working 'most of the time.' Had the car out last weekend and the AC worked fine for 20 min then it felt like the cool english news capread air stopped. Maybe 20 min later the cool air came back on (blower and cool nobs on full the whole time). I'm not sire if it it just a loose connection somewhere or some other issue. Your guidance in getting to the source of this issue will be greatly appreciated.

[tmadden2]

Originally Posted by Gabar

AC worked fine for 20 min then it felt like the cool air stopped. Maybe 20 min later the cool air came back on (blower and cool nobs on full the whole time).

The on/off action will happen when the compressor freezes up. You can leave the fan knob on high and the thermostat knob down a few levels to see if this helps cycle it on and off more so it doesn’t run itself to death. The thermostat switches can fail, especially if the long tube part gets damaged. You can also make sure the system has a full refrigerant charge (this needs to be done annually with r-134a and the OEM hoses). The A/C system is a mess on these cars, but there’s no shortage of helpful advice on here to troubleshoot.

[uwanna]

Originally Posted by tmadden2

The on/off action will happen when the compressor freezes up. You can leave the fan knob on high and the thermostat knob down a few levels to see if this helps cycle it on and off more so it doesn’t run itself to death. The thermostat switches can fail, especially if the long tube part gets damaged. You can also make sure the system has a full refrigerant charge (this needs to be done annually with r-134a and the OEM hoses). The A/C system is a mess on these cars, but there’s no shortage of helpful advice on here to troubleshoot.

Just a nit, but I think you meant to say that the evaporator freezes up
NOT the compressor. Other than that your advice is right on.

[Jack Stands]

I have the same issue with leaking 134a, but hope that swapping out to Kuehl’s barrier hoses will help keep the refrigerant in the system.

[86 911 Targa]

Originally Posted by Gabar

Hello everyone,,,
Our 1984 911 was converted to 134 about 4 years ago. Recently had leaks in the system fixed and it seems to be working 'most of the time.' Had the car out last weekend and the AC worked fine for 20 min then it felt like the cool air stopped. Maybe 20 min later the cool air came back on (blower and cool nobs on full the whole time). I'm not sire if it it just a loose connection somewhere or some other issue. Your guidance in getting to the source of this issue will be greatly appreciated.

If it is freeze-up, increase the fan speed, back off the temp setting.

Then let's see.

Gerry

[T77911S]

what Gerry said.

freezing up.

when mine would freeze up it would not thaw out unless I turned it off.

[kuehl]

Originally Posted by Gabar

Hello everyone,,,
...... felt like the cool air stopped. Maybe 20 min later the cool air came back on (blower and cool nobs on full the whole time). .

Can you further clarify "cool air stopped". Do you mean:
A) Air stopped coming out of the AC vent above the radio?
B) Air was coming out of the vent, however it was not as cold as before?

Thank you

[GH85Carrera]

Usually the evaporator freeze up is accompanied by a funky smell. Turn the temperature knob to full warm, and let it blow at max. In the heat, the ice will melt in short order.

[kuehl]

Let the op clarify the question.