The cooling fan on my 2008 XJ VDP imparts quite a bit of vibration when on high speed. It comes and goes in a resonant fashion, but that seems to me to be either imbalance or a bearing going out. Has anyone else run into this? I have some other cooling work to be done, so if I have to replace it now is the time to do it, but at $600-$700 I don't want to replace it if I should be looking somewhere else in the mechanism.

Thanks,
Dave