Squeaking Heater Fan Fixed For Free

If you've ever had a squeaking or chirping noise in your car, you'll appreciate just how much it can drive you insane. It's even more annoying when it's a heater fan, as these are on pretty much constantly in your car.

About a minute is all you can safely endure without lasting side effects, so after my 45 minute commute to work I had high blood pressure and a serious eye twitch.

Thankfully, it only took 20mins and some Muc-Off Wet Oil to completely solve the problem, sparing myself from looking like Tweek from South Park.

Initially, I couldn't tell what was actually making the noise, my first thought was some trim parts vibrating against each other. Oddly, the chirping would only happen at certain temperatures, and sods law, never when I tried to show someone else...However, I did eventually link the fan speed to the frequency of chirp. Bingo.

As you might expect, the fan is buried in the heart of the dash board up behind the glove box. Thankfully, the BMW boffins had a look in their crystal ball, saw it was a common problem on the E90 series, and designed the fan to be relatively accessible, making this a job you can definitely do yourself.

Skip over to the workshop to read the full how-to guide to removing, fixing the squeak and refitting the heater blower fan.

Prior to removing the glove box you've got to remove the hush panel and the cup holders.

After removing the cup holders, I took the opportunity to give them and the surrounding area a quick clean.

With the glovebox out the way, the fan is in sight. To actually get the fan out, you've got to remove the heater ducting.

This gives you a clear route to the fan.

There are a few electrical connections to unclip, then the whole fan unit twists out. It's like a large quarter turn fixing, once twisted the fan unit will simply fall away from the housing.

The corrosion on the fan centre shaft is caused by moisture ingress through the intake bulkhead. It's this corrosion that's causing the squeaking and chirping. If the corrosion is too bad, you may need to replace the fan at this point.

As moisture was causing the problem, I went with Muc-Off Wet Oil, if it works on Mountain Bikes it should work just fine here.

You need to apply it at the interface of the fan centre shaft and the motor.

All oiled up I reconnected the fan to test the fix. I was shocked just how fast the fan spins, the dash must do a great job of damping the sound as it's pretty darn loud. Also, you definitely wouldn't want to catch a finger in the fins, I imagine it would make you wince somewhat.

This may not be a permanent fix, but it's quite straight forward to do and, importantly, cheap. Fortunately, after 6 months / 8000 miles the chirping hasn't returned, fingers crossed it doesn't.