When my a.c. compressor is running I hear a vibration. So I got under the car and I noticed the crank pulley has a very slight wobble to it. The vibration is not coming from the compressor. It seems to be coming from the crank pulley. I spayed wd40 between pulley and block and the vibration went away briefly. The belt was replaced 5k+ miles ago. I now have 83,000 miles on odo. Is the crank pulley failing?