2006 Corolla Vibration Noise At Idle When Engine Cooling Fan Is On - Toyota Corolla, Chevy Prizm (1998-2008)

Ok - not sure how to describe this.... But, when I am at a stoplight at idle and it seems that the fan goes onto cool the engine, it kicks in with this sound vibration....like a card in the spokes of a wheel....d d d d d d d d d d d.....The car itself doesn't feel like it's vibrating, it just sounds like it's vibrating. This started last year and would only do it for little periods at a time or if I moved the car a little it would stop and that would be it. Now - it just does it everytime I'm stopped at a light and it is loud. It doesn't seem to do this as much if I'm just in park though it has done it and I've stepped outside to see if I can heart it....nothing. Also - my lights seem to deem a little when this particular fan or whatever it is turns on. I'm thinking I need to check my battery cables to see how clean they are. Any thoughts on this noise? It's starting to drive me bonkers because it's so loud.

If the main battery is more than 5 years old, might be time to start thinking of a new battery to keep up. Sounds like when the engine is loaded (idling in gear) the engine might be moving enough to cause something to contact with the fan blades. Might be able to replicate this load by setting the parking brake, standing on the brakes and idling with the car in gear, while someone takes a peek under the hood. Just idling on its own in park/neutral is not enough of a load to cause the engine to shift much. Might also try turning on the A/C and other accessories, that will load the engine quite a bit.

Could be anything from a broken fan blade, to something touching the fan blade (loose hose, debris stuck in radiator), damaged fan shroud (moves when engine is loaded) or even bent fins on the radiator.

Niiiice..... I actually just replaced the battery a few months ago because of the dimming. I don't know if it's gotten worse or if I'm just noticing it more (probably just noticing it more). As for the annoying d d d d d d d d d It's been doing it for so long I was just like...whatever...but now it is just downright annoying because it does it every stinkin' time. I'll have to go check out a schematic to see what where this stuff is. Hopefully I'll have time to do this tonight.