car whining when A/C turned on

[edge19lw]

I had my timing belt done around a year ago and I know that to remove the timing belt you have to remove the fan/accessory belt also. but every time i turn on the A/C the rpm's drop a little bit then settle, and while i hit around 1200-1300rpm the car whines then stops as i go higher in rpm's. Was the belt tightened too much or too little? Or do i maybe need a new belt?


(At idle I also hear every half second a rattling noise and I believe its coming from one of the accessories that the belt spins, the mechanic had said it was the water pump and said it would stop as the belt got looser but that never happened, any thoughts?) Thank you !

[drmarcj]

Just to clarify: the serpentine (accessory) belt runs the AC, but it also runs the power steering and other stuff, so you can't just take it off without disabling other important stuff (unlike the B5). I don't think it's the tensioner because that would make a noise all the time not just when the AC is running.

Also FYI: water pump runs off the timing belt. Was it changed when you did the timing belt?

[bavaria75]

That your RPM drop a little seems normal, as the motor now needs to power the ac compressor what actually takes quite a load.
As for the whining I assume it's just during steering. I have a similar think ongoing. Seems like just with AC on and steer. Not on a straight.
You might check the Power Sterring fluid level.
Good luck and keep us posted.
Timing belt is only for the timing of the engine and the waterpump, has nothing to do with the AC, generator or PSPump.

[edge19lw]

yes the water pump was changed at the time as well, the whining noise was never there before the timing belt was done nor was this rattling noise, (i didnt get it done at the dealer either)

[bavaria75]

Rattling noise. Is this just when the car stands and you are in front of the car? Like a higher pitch sound?
As for the AC on and whining noise, the whole waterpump think just doesn't add up right now. I still think it is your Power Steering pump.
Or maybe a defective Waterpump, but this would not explain the AC involvement.

[edge19lw]

ya the rattling noise is only heard from outside the car while it is sitting and idling (you cant really hear it inside the cabin). It is also a low pitch rattle. I like the idea of the steering pump causing the whining noise since it is run on the same belt as the A/C so that may fit the problem.

Going back to the rattling noise though, i cant really locate the rattle but im going to take off the timing belt covers to maybe get a better listen to it

[bavaria75]

I have a rattling noise and it is a small kind a leaf spring at the belt tensioner I believe. If you underneath the car and look right up in the front (radiator fan ) middle of the engine you will see the belt tensioner and a little metal flag or lef spring coming out in the middle . I believe at a certain rpm this will vibrate and make the noise. Stuffed some paper between the hole and the leafspring where its guided and it went away.

[edge19lw]

lol sounds like a plan bavaria im gonna take up your idea and see what happens xD

[edge19lw]

hey bavaria was the rattling noise you had also continuous (like every half second sorta like pulsing) ?

[bavaria75]

No was permanent, but I just heard the noise when the car was in idle and I stand right in front of the car. Or in the garage with the windows down.

[Splattj]

Any update on this?

I have the exact same symptoms going on. They also started after my timing belt replacement which included a water pump, tensioner, pulleys, and belt. I have a slow rattle at idle and I hear a whine when I turn on my A/C. I think the tension might just be a little on the high side. Are the tensioners adjustable?

[edge19lw]

thats exactly what I was thinking about the tensions being a little high , i'll check the bentley manual to see if where the tension can be adjusted

[VancityA4]

I just got my timing belt changed and have the exact same problem with the continuous rattling at idle. Anyone figure out what is causing this? I had the timing belt, accessory belt, tensioner, and water pump changed.

[edge19lw]

this is really annoying isn't it? It just makes all the nice quality of the car not shine because of that ugly rattling sound

[edge19lw]

I'm going to have to say that it has to do something with the belt being to tight or the tensioner rattling maybe, it has to be one of the 2

[CO AVANT]

The tensioner to the serpentine belt works off its own sprung force so I don't think your belts are too tight. Check to see if your timing belt is tight by taking off the cover. I've seen people not properly compress/decompress the timing belt tensioner and ruin it. Make sure it's good and tight. Make sure the belt is spinning all the accessories the correct way. Wouldn't think it's possible to put the serpentine belt on wrong, but I have seen stranger things before...

[bavaria75]

So we dealing with two issues here.

A/C on and whining noise - current status - it might be the Timing or accessory belt tenstion

Rattling at idle - mine was the holding strip on the accessory tentioner. If you remove the bottom engine cover and look up between the engine and the fans you will see the little spring/strip/metal belt inside the tentioner (used to hold the tensioner retracted when installing the accessory belt. This strip is loose and vibrating, making the noise.

[04QuattroTurbo]

hey bavaria was the rattling noise you had also continuous (like every half second sorta like pulsing) ?

I got the same problem, when the engine is cold, and at idle with the AC, I can feel it pulsing from the gas pedal.

[VancityA4]

Thanks to everyone for all the help. The culprit to my rattling was found to be a loose accessory belt tensioner. This would explain why the rattling would get louder when the A/C was turned on. Installed a new tensioner and everything is good.

[edge19lw]

i actually took off my timing belt cover and found that every time the timing belt made a full revolution that it makes the rattle, I'm going to take off the bottom cover again and see if its the accessory tensioner or what else it could be (its just so damn crammed in there lol)