Does your A/C work fine when you first start the car but then fail after a while, especially on hotter days? There is a good chance your AC compressor clutch has worn enough to prevent it from engaging when hot. If you are lucky, you may be able to fix it for free by removing some spacers! If you are less lucky (but not terribly unlucky!) you may be able to fix it with a new A/C clutch.

The car in this video is a 2005 Volvo S40. Everything in here should apply pretty exactly to other later model Volvos, and most of it carries over to any car.

As always, don't try this if you don't feel up to it! Work with jackstands if you have to work in the wheel well on your car, don't get under a car held up by a scissor jack!

2021 Update: I don't frequently answer questions on here because it has been years since I did this and I'm not a regular mechanic, this is my father's car, not mine, and basically anything that isn't this video... I probably don't remember. 4 years later, it is still working though, so that's a good sign.