car's air conditioner not working...

[phantasus]

i got a Renault MeganeII hatchback 5doors automatic (metil blue!) its got like... 7-8 months whit me? its my first car. (ok, it is a griffin but is disguised as a car sooo non-belivers wont be scared,hehe ) . the a/c is not working ( and weather here is too hot), it got like 3 days like that. im getting someone to fix it but i want to know why this happened (so i can prevent it).
any one knows why this happened? or how can i prevent it? or if it is a common problem or something?

[otrstf]

A/C is one of those annoying problems you almost have to pay someone else to fix.  There are several flavors of problems, and I couldn't tell from your description.  For instance:

1.  If you turn on the A/C switch and nothing happens, that's an electrical problem, and usually a fuse, a loose wire or bad switch. Could be as cheap as a buck!
2.  If the A/C turns on, but there is little or no cold, you have a coolant leak.  In the US, the law requires you pay a certified mechanic to fix this, to prevent venting the remaining coolant.  Middle expensive.
3.  If the A/C clunks, makes odd noises, etc. , you have a bad compressor, or an animal trapped under your hood. Now we're talking relacement, usually. More expensive.

As far as things to do to prevent this happening again...about all you can do is have it checked imediatly before the weather heats up for the summer. the mechan ic might be able to add a little coolant, cheap. Otherwise, remember that the fans that blow the cool air into the car cost almost nothing to run, compared to the compressor. so turn up the temperature a little and let the breeze blow.  also, once the A/C has cooled the car, turn it to "Recirculate" and turn it a little warmer.

[Xepher]

Yeah, we need a few more symptoms/signs to guess what's going on.

1. Is it blowing air, but it's just not cold?
2. Any strange noises?
3. Do the lights on the controls all work as they should? Do they show it on/working?
4. When you turn it on/off while parked, does the engine sound change? How so, describe it?
5. If you can look under the hood and actually find the AC compressor, see if the center bit of the pulley is actually turning when it's on (and not turning when it's off.) The outside of the pulley should turn with the belt at all times. Try having someone turn the AC on/off while you watch, see if it "clunks" into spinning the center/shaft.

[phantasus]

it do blows air but it is hot. no weird noises or anything, controls ( buttons and ligths ) seem to be working.

[Xepher]

Well, if the compressor is actually turning on (center part of pulley moving as per #5 or hearing it kick in as per #4) then all that's really left is a coolant leak/problem. With luck, it's just one of the lines has a small puncture and can be patched... that plus the cost of refilling the coolant is usually pretty cheap. If the compressor is busted though, it can be several hundred dollars. If the leak is in the evaporator or other "expensive" bit of the system, it can be kind of expensive too, but it really depends on the car. Pretty much have to take it to a mechanic unless you know someone personally that can fix AC systems.