Fan squeak/whistle

[rfernatt]

Ok, I think I've determined that my smart isn't ready to transition to cooler weather.

This week I've noticed that the ventilation fan is making a squeaky/whistly noise that is more noticeable at lower fan speeds. It goes away if the fan is shutoff, so I'm pretty sure that's it.

Can you get to the fan/motor easily in the smart? I had a Mitsu Lancer that I removed the fan from periodically due to mice, but the smart has been garaged, so I don't think mice are involved.

Any thoughts?

[karen103a]

You sure it's a squeak/whistle? Quite often a twig or something will find its way down a car's vents and into the blower motor, where it rat-a-tats against the rotating blades. Our Hyundai Elantra has one down there.

[SmartJoeMN]

My Fortwo would do this when it was cold outside. I always meant to bring it in but never got around to it.

[rfernatt]

Ok, I think I solved this problem on my car. The slight whistly noise at low speeds turned into a low pitched wah-wah noise (I know, funny noise names ) at higher fan speeds. It definitely sounded like something was amiss, so I started poking around and decided to pull out the in-cabin air filter to check.

When I first touched one of the releases on the air filter cover panel, it fell off in the floor. So, I don't think it was securely fastened in place which may have lead to the whistle if there was a gap around this panel. Secondly, I theorize that the wah-wah sound may have been vacuum from the fan sucking this panel closed and then it reopening itself due to tension. My car had extensive AC work done recently, expansion valve and surrounding parts replaced, which I believe are in the same area. The dealer may not have put this cover back in place properly or perhaps something jarred it loose.

Regardless, I pulled the cabin filter which wasn't too dirty, cleaned it anyway, and securely replaced the filter and cover panel and presto - no more weird noises. If you have odd fan noises, you may want to check this panel and the filter as well.