u/sabbota

Greetings,

I have a 2014 Mazda6 GT with approximately 39K miles. I am trying to see if anyone has experienced my issue and what was their fixes. I also want to decide whether to go ahead with A/C repair based on the 1st mechanic diagnosis or get a second opinion.

A/C had been working normally. I took the car on a ~3hour trip and parked it at the hotel valet (the only option I had without losing much time) to attend an event. When I got the car back after it had been parked outside in the sun all day, I noticed the following:

• Initially, the A/C seemed to cool normally while idling upon starting the car and I can hear the compressor engage. Once I drove >40 mph, I lost cold air and started hearing a weak hissing/whooshing sound through the vents and somewhat under the hood. The sound increases proportionally with the rpm (not very loud). This pattern is pretty odd to me and couldn't find anything similar online.
• While the compressor would engage initially upon start, once the A/C became warm I could no longer hear it re-engaging when cycling the A/C on/off button.
• Blower strength stayed almost the same, only cold air loss and the unusual sound.
• Over the next day, while taking it to a mechanic, I noticed that it would sometimes cool intermittently when stopped in traffic, then randomly lose cold air again.

I took it to a small local shop that specialized in automative A/C and electrical work, a mechanic with apparently many years of experience. He recovered ~0.80 lb of refrigerant. The car specifies ~1.135 lb (0.515 kg), so that is roughly 30% low. He added a small amount of refrigerant plus Green dye, as there were no obvious signs of leaking, yet.

After checking the refrigerant-line temperature and hoses, he believes the system has an internal restriction/clogging and strongly recommended NOT to turn the compressor again until changing the expansion valve and condenser, to avoid destroying the compressor. Attached photo shows the observations on the A/C line temperatures.

The circled line on the photo is cold (not freezing cold), which he thought should be hot, and that is what led him to conclude the system is clogged/restricted.

My questions for anyone familiar with car/MAZDA 6 A/C issues or have experienced similar symptoms:

• Does this temperature pattern actually support a restricted condenser/problem with the expansion valve?
• How does the hissing/whooshing/whizzing sound that increases slightly with RPM fit into this diagnosis?
• Would you trust aftermarket condenser/expansion valve here, or is this one of those repairs where OEM Mazda parts are worth the additional cost?
• He mentioned that replacing the condenser would require removing the front bumper. Is bumper removal normally required/advisable for condenser replacement on this model, or can the condenser reasonably be replaced without removing it?
• Given that the system was roughly 30% low on refrigerant, could low refrigerant alone cause this temperature pattern and compressor behavior, or does the cold liquid line make a restriction more likely?

Has anyone with a 2014–2016 Mazda6 experienced similar symptoms? If so, what ultimately turned out to be the problem?

I realize this is a long post, so any insight on any of these points would be greatly appreciated. I have experienced A/C issues with my previous car, but not as odd as this one, at least to me.

Thanks!