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Cobalt doesn't blow cold

Scratch on Tue November 16, 2010 10:43 AM User is offline

Year: 2008
Make: Chevrolet
Model: Cobalt
Engine Size: 2.2L
Refrigerant Type: R134
Ambient Temp: 68
Pressure Low: 50
Pressure High: 100
Country of Origin: United States

Please ignore the low and high side readings as I just have a question about conversion. I would like to remove the R134 and go to a R12 system. What is involved in such a task? I read that all O rings and the refrigerant oil have to be replaced. Is there anything that must be done?

scott johnson

iceman2555 on Tue November 16, 2010 11:58 PM User is offlineView users profile

My first question would be WHY?
I could not find any information concerning the legality of this, however, it is seriously doubtful that this would be legal under current regulations. But back to the why part. The issue, it is assumed is to increase system performance...make it cool better, correct? Why is it expected that this change will offer this benefit? Does the system not function properly now...what is the problem and what has been done to rectify it. Have serviced several of these vehicles...and have not seen any abnormal cooling issues.
That being said, the compressor control devices were not calibrated for operation with R12. This could present serious issues with compressor longevity and cooling. It is possible that the drop in operational pressures, both high and low side due to the increase heat transfer of the modern condenser (vs older R12 tube and fin) would result in the compressor remaining in a 'de stroked' position. When this occurs, lubricant flow is disrupted and of course, the result is loss of the compressor.
The TXV is calibrated for 134a and this change could also present operational issue. A change in reference signals from the TXV will affect compressor performance also as well as evaporator efficiency. It is highly doubtful that this change will do anything but cause an increase in expenditures and no increase in cooling.
But that is simply my $.02 worth.
Heck...I think you should go for it.....screw the legal aspect.....and the fact that no AC tech will touch your vehicle in the future....and then let us know what happens. After can always be repaired and all new parts re installed...could be a very expensive test....but sure would like to know the results.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

mk378 on Wed November 17, 2010 8:06 AM User is offline

I rented a Cobalt about that time and drove all over the Nevada desert. The stock system seemed quite good. If you're not getting good performance there is probably something wrong. R-12 is not a magical substance that gets cold no matter what.

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