When I start the fan in my car it is fine. But if I have the A/C on and I start the fan I am hearing a grinding or buzzing noise coming from the engine bay. I have a MY01 with approximately 62k miles. Has anyone had this problem before? What part of the A/C system is malfunctioning?

Any help is greatly appreciated.

Thanks,
Eric

 

Pop the hood and see what fan motor is making the noise.
There are 2 cooling fans, most likely one has gone bad.
Unless you are talking about a noise heard inside the car from the HVAC blower motor.

 

Does the noise vary with the intensity of the fan (eg. 1 light compared to 3 or 4 lights)? If the rattle increases with interior fan speed, then it's that fan. If not then it's something in the engine bay.
Like Slow says, it could be one of the rad fans or it could be the A/C compressor.

 

Leave the ign key on, select AC on, and blower on. If the noise is under hood, it's one of the cooling fans. This will eliminate the compressor as well, since the engine won't be running.

 

It makes the noise as I start the A/C. Then it goes away briefly after a few seconds. I am going to go out and try it with the engine off.

 

Problem solved. Wow, that was interesting. I got a flashlight and listened for the buzzing noise. I put the light to where the noise was coming from and found my ZTEC carbon fiber heat shield had melted the rivets out and fallen into the engine bay. When I turned the A/C on it was the heatshield getting chewed up. I should've used the flashlight the first time and I would've caught this. Sorry! Thanks for the input.

 

Kewl

 

Another engine grenade averted.

 

Locky Locky