Mazda Repair: Mazda Air condioning, r 134a, ac works

Question
1998 Protege. 4 cyl. AC freon level is fine. AC works IF outside temps are 75 to 80 or less. Nice and cold. However if temps are 90 or higher the cold air stops. Fan still goes but pushes ambient air. Suggestions appreciated. I assume compressor disengages for some reason. What should I check?

Thanks Steve

Answer
Not my specific area of expertise, nor car.  However, the primary issue is likely that the freon level is not correct.  The system needs to be evacuated, filtered and vacuum processed then recharged as a sealed system to insure that no air enters the system, for one and to insure that the correct metered amount of charge and oil is high side charged.  With R-134a if too much is used the system will not function properly if too little same story.  Too little will result in poor temperatures and the compressor will run short cycles.  Too high usually leads to clutch slippage or freezing and compressor wear.  A poorly operating system with compressor internal wear issues would be more pronounced in hotter ambient situations than in less challenging cooler environments.

If the system has not been opened replacement of the receiver/drier assembly is advised since it captures moisture and scale from the system, a filter of sorts.  After a decade of use it is over due.  In vehicles over 7 years of age it is common to have annual seepage and systems require yearly recharging.  Consider annual evacuation and recharging of freon and oil normal maintenance similar to an engine oil change.  Its an often neglected area until a failure occurs.

Hope this helps you out.

service@miatashop.com

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