Vibration when AC is activated. Help.

[olsan100]

Background: Fan blower seized up. Purchased a new blower. Installed it. It worked fine. Noticed AC was blowing cold anymore. Had local indy convert it to R34.

Problem: Now, when I turn the AC on, usually after a few minutes or longer, eventually there will be a vibrating noise, like the blower is out of balance. But, when I turn the AC button off, the vibrating noise will stop. It will always eventually happen, just not instantly when the AC button goes on. But, it will always stop doing it instantly when the AC is turned off.

Does the AC put an extra load on the blower, and cause it vibrate "out of balance"? Or is there something else, maybe within the ac system, that could be vibrating?

Any thoughts would be greatly appreciated!!

[colo525i]

If the fan is at the same speed with the a/c on and off, its not the fan. The electric cooling fan on the front of the car is your likely culprit. The mounts may be hardened. I can feel mine switch to high speed through the steering column. My only other guess is a vibration by the a/c compressor itself. Pop the hood and take a look at both places.

[Alpinewhite]

Like it has already been said. When the AC is switched on and you go in slow speeds (or stay in a single place) more air is needed by the AC and radiator fins to exchange heat. This results in the electric Auxillary fan in the front of the car to go in high speeds that is mostly probably why you feel vibrations. I too can feel the vibration in the steering column when it goes in high speeds. I dont know if it is a serious problem that needs immediate attention.

Arun

[RobPatt]

....if what you can see looks fine, rotate and check the rest... a belt w/a bit of the ribs on the inside missing will make you feel engine vibrations.... ask me how i know... :D