kmaiella

air conditioner issue

4 posts in this topic

Hello, I am having difficulties with a Mazda 626 v 4 cylinder engine air conditioner. It seems as though the air conditioner works great but only if I am going approximately 40 miles per hour. Otherwise the air conditioner does not get cold it just simply blows warm air. Any idea as to what could be causing this? Thanks:)

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Get a shop to refill the AC system.

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If it didn't work at all, and/or you had leaks, I would agree a shop is best since it would require draining / filling & that's ultimately bad for the environment.

However, since you get *some* cooling at high revs, your system is probably just a little low and needs to be topped off. If you want to do it yourself, you'll need an r134a manifold gauge set, with both high and low (blue and red) gauges. You can get a set for roughly $60 or so, and then also a can or two of r134a. There's lots of videos on how to do this, but basically you would hook the gauges up to your high and low Schrader valves (located on your A/C refrigerant lines in the engine compartment, passenger side and behind the radiator.) Then you'd watch the numbers on the gauges as you run the system, and slowly add refrigerant until the numbers are within spec. The specification of perfect high/low pressures is widely available and should be universal to all r134a systems. Whatever specification you use should be relative to the ambient outside temperature: http://rechargeac.com/how-to/ac-system-pressure-chart

Here's a decent, well written article explaining the various components of your typical automotive a/c system: http://auto.howstuffworks.com/automotive-air-conditioning.htm Give that a read, it'll take you about 15 minutes to get a good understanding of the system, and you'll be well prepared to understand the DIY approach.

The key is to get the numbers within the right range as closely as possible. If you are under, obviously it won't run well. But more is definitely not better - if you put too much in, it will also run badly or not at all (and possibly spring a leak.) If you read the article above, explaining the system, you'll understand why - the refrigerant has to be able to revert to gas form.

If you nail it and get the numbers perfect, you'll be rewarded with some nice, cold air from your system. It's not all that hard and kinda fun to do, actually. And once you know how to top it off correctly, you'll be prepared for that eventuality if your system runs low again.

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Thank you for your wonderful advice. Refilling the A/C was not sufficient. So after reading your advice it was found that your comments and links were most helpful. Ultimately, there needed to be adjustments made in addition to topping it off. Apparently, there was some sort of pressure issue which I don't fully understand how to explain it here. But once the pressure issue was found, adjustments ere made, and the A/C was refilled, now my vehicle cools fantastically when I start up the vehicle and even when idling. Thank you so much for your very descriptive as your post was most helpful.  

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