2.5 years and I have never used the AC. Yesterday I flushed the cooling system, when finished I tested the heat and AC. When I turn the AC on a loud clanking noise starts, the noise is consistant no matter which fan setting. More noticable inside car and annoying. Is this normal? Seems really loud.

 

Can you tell where it's coming from in the car? Like it's coming from the Glove box area, behind the radio...ect

 

Doesn't sound normal. Odd that it's inside the car. Depending on the type of sound, maybe there's a piece of something-or-other in your vents. If you can hear it in the engine bay, check your compressor and/or belts.
Why wouldn't you use the AC for 2.5 years?!?

 

My car sounds like a Freight Liner at idle with the A/C on. I think it is the throw out bearing rattling. Anyway, I have heard other owners comment on this and their comments are the same. So, if what you are hearing is coming from under the hood and is heard only at idle I'd say it is normal.

 

you say you never used the A/C but have you ever used the defrost???? Pretty sure the A/C comes on when you use defrost, I remember a thread talking about that

 

yeah A/C definitely comes on when you use defroster. As for that sound, it does not sound normal at all. maybe post a video of what it sounds like to better troubleshoot it from here

 

I hear it in the engine bay, just hear it more clearly in cabin. Just don't use the AC, very rarely have in any car I've owned.

 

I've heard the throw out bearing rattling sometimes at a stop light or when just warming car up, it only rattles occsionally, press clutch pedal and release it stops rattling. I was thinking also would turning on the AC amplify the bearing ratlling? It was alot louder rattle than what I'm use to hearing from the throw out bearing. I turned the AC on again yesterday, sounded normal, no rattle, turned on and off and would not rattle. Next time I hear the throw at bearing rattling I'm going to turn on AC to see.

 

Yes, the AC comes on in defrost, have used defrost alot, never heard any unuasual sounds.

 

yea that doesnt sound to normal.. if you havnt used ur AC in 2.5 years and just wondering about the noise i really wouldnt worry about it...

 

then maybe it's the A/C radiator fan rubbing?? Perhaps you somehow messed something up when did the fluid change?? Since you didn't have this problem before you did that makes me belive something happened when you did the work. I once changed the oil on my girl friend's car and somehow bumped the radiator fan cover just slightly and it was rubbing