Odd vibration in 88 coupe

[hflynn]

I hope this helps a few people. I have been dealing with a subtle and inconsistent vibration / hum for the last couple of weeks. The problem was diagnosed as a wheel bearing and I replaced both fronts (the left bearing was in pretty bad shape). This helped but didn't eliminate.

Turns out that the engine cooling fan was coming apart in a couple of places, the hub and one blade. The crack in the hub was rubbing the alternator belt and causing a vibration. It was discovered because I complained of having replaced the belt twice in the last year and a third didn't make sense.