My Mazda won't chill out

September 14, 2007 8:48 AM

Need help troubleshooting automotive A/C issue.

A/C system blows very cold until the outside temperature reaches about 95 degrees, at which point it blows air that is only about 60% as cool; using a digital thermometer to measure. (Noticeable in Texas heat!). The air speed stays the same but it just isn’t as cool and it feels like "outside air even if system is on recirculate. It also takes about 5 minutes for air to start blowing cold if the car has been parked out in the sun. The Mazda dealer said this is normal and that the system if fine.

Any ideas? Low or bad freon? Compressor? A loose belt? Is something plugged up? Should I take to an independent shop and have them evacuate/recharge the system?

posted by punkfloyd to Travel & Transportation (8 answers total)

Your AC just moves heat from inside the car to outside. As the outside temp goes up it becomes increasingly more difficult for the AC to dissipate the heat to the outside. I suggest tinting your windows to reduce the AC load.
posted by caddis at 8:53 AM on September 14, 2007

is there a "recirculate" vs "outside air" switch in your AC system? Does turning it to "recirculate" help? That way, you're only asking the AC system to cool the air from the internal temp to the desired temp, rather than the hue difference of ourside temp to desired temp.
posted by cosmicbandito at 9:15 AM on September 14, 2007

Use sun visor or shade of tree/building whenever possible.
When you get in roll down windows and turn on AC to high.
This will mostly just help vent out the hot air from inside your car, and give the AC system a chance to blow cooler when some hot air has vented.
After a few minutes roll up windows.
Then you can put AC to max/recirc or wait a few minutes.
That is my routine, and it still takes 5-10 minutes on a hot day.
Also stop and go traffic will take it longer to feel cooler.
posted by sailormouth at 9:24 AM on September 14, 2007

Is it a Mazda3? There is a fairly simple hack to trick the AC to make the air temperature colder. I'll dig up a link for you.
posted by Doohickie at 9:25 AM on September 14, 2007

Is it an early Mazda 3? A buddy of mine has one of those with the same problem (AC not effective when it's hot, heat when it's cold). After much back-and-forth with the dealer, it turned out that there's some kind of plastic flap within the system that tends to go wrong and let in outside air. Apparently it's fairly common - on preview, maybe it's related to Doohickie's post.
posted by pocams at 9:28 AM on September 14, 2007

Response by poster: Mazda6... and there are some good online forums that mentioned the flap thing...but I can't convince dealer to follow up.
posted by punkfloyd at 10:33 AM on September 14, 2007

On some Mazda forums, if there is a user named southpawboston, he is the one to ask. He's an electrical engineer and really gets to know his cars. If you haven't run across him, email me and I'll give you his contact information if you would like (I got to know him when he owned a Hyundai Elantra).
posted by Doohickie at 10:53 AM on September 14, 2007

My car - Ford Crown Victoria OLD SKOOL - used to struggle with hotter days, but be cool enough on not so hot days. I figured it was a cooling capacity issue, so I went and got one of those recharging cans from Walmart (check compatibility of coolant gas) and it worked a treat.

The system was a little down on volume and that was all it needed to sort it out. It's like a fridge*, now.



* a very ugly, huge and rusting fridge that I wouldn't eat anything that was stored in it
posted by Brockles at 11:29 AM on September 14, 2007