2004 Chevy Cavalier Clicking under hood

The "check engine" light is an indicator for a system that monitors many electronic functions in the system, also called the "malfunction indicator lamp" (MIL). It can come on for any of hundreds of different causes from any of the systems that the computer monitors. Some are very important and can lead to further component or engine damage and some are emissions related not as serious but still a problem and need to be repaired.

Your first step is to have the computer scanned to retrieve the trouble codes that were set when the check engine light came on. Those codes will give you specific information about what the computer saw and will get you pointed in the right direction to find your problem. With a 1996 or newer and some 95 cars and you have an AutoZone or Advanced auto parts in your area, they will read them for free. Once you have these code numbers, we can be a lot more specific about what your problem may be.

The noises could be most anything. Get the codes first and see if they are related. In the meantime, try to pinpoint just where the noise is originating.

Thanks so much for the prompt response. My check engine light is "not" on. I'm not able to check for trouble codes. The sound may be coming from under the dash. I have had problems with my fan assembly in the past. The A/C works as long as the car is moving. While idling, it will only blow hot air. Could the fan be the problem? If so, will this damage my engine if not taken care of immediately. Could the serpentine belt make this noise if it needs replaced?

Sorry, I misread the question.

Do definitely need to follow up on this and get some better info on the problem. The noise is in the engine but it may be under the dash is telling me nothing. Yes, if your cooling fan is not working it will mess up your A/C and take out your compressor. You need to get some more accurate info on this.