How To Fix Your Squeaking/Screeching GM Blower Motor
written by Randy Mullins
photos by Randy Mullins
[Randy wrote me a note thanking me for my article about the blower motor replacement - thanks Randy! He fixed his blower motor instead of replacing it. Randy was kind enough to send an article he wrote showing how to repair the bearing in the blower motor. I should have done this to my motor. It probably was its only problem. My new motor is already squeeking.... Big thanks to Randy for pulling this together. You can read this article at his blog as well: http://blognessmonster.wordpress.com/]
Squealing and screeching sounds coming from beneath the passenger-side dash when the A/C, heat / blower motor is on. The sounds happen in cold or humid weather, and especially when hitting bumps in the road or slamming on the brakes. The sounds happen less when blower is on higher settings and all the time on lower speeds. When shutting off the blower, the screeching sound slowly dies away.
Short Answer & Good News:
In my case the problem was that the motor housing bearing had become so dried out that it seized up on the motor shaft. The good news is that this is a problem that can in most cases be fixed without having to purchase a new blower motor. The screeching noise was happening because the shaft and bearing were spinning together inside the motor mount. At slower speeds it was easier for the bearing to spin in the mount than it was for the shaft to spin in the bearing, explaining why I could avoid the noise by turning the blower up.
This photo shows the bearing (which is supposed to be mounted in the motor housing cap) stuck to the motor shaft.
Fixing the GM Screeching Blower Motor on a 1998 Buick Century
1. Remove the passenger side kick panel. Follow the steps on page one of the replacement instructions to remove the passenger-side kick panel. Note: I used the nail puller on a very small hammer to remove the 3 plastic push-in clips and it worked pretty well.
2. First try spraying WD-40 in through the bottom hole of the motor mount.
You can see the end of the motor shaft just inside the raised 'nipple' on the motor housing. Inside that nipple is a bearing that the shaft is spinning inside of and those are the two parts that seized up from drying out. By spraying WD-40 in there you may be able to free them up without having to remove the blower motor.
And Here is a closer view:
3. If that doesn't work, follow the steps on page one of the instructions to completely remove the blower motor. Note: use a 5.5mm socket to remove the three screws. Note 2: Remove the rubber air tube by pinching and pulling out.
Once the motor is free, hold it fan-side-up as it was mounted and insert the WD-40 spray tube in through the hole where the air intake tube used to be. CAUTION: only spray a very little amount of WD-40 - you don't want to douse the motor wires. Spin the fan half a turn and spray a little more WD-40 to get the other side. Give it a few minutes to work in while spinning the fan a few times.
Now you should be able to spin the fan without the motor making any noise.
If the screeching noise is still happening from your blower motor, either the noise is coming from a different part of the motor, in which case I'm little help, or you just haven't gotten the bearing loosened from the motor shaft. If the later is the case, read on. If not, you may want to get yourself a new blower motor.
Here Is What I did To Figure Out The Steps Above:
I decided to pull the top cap off the motor. Since I didn't know there was a bearing in there yet, I had not sprayed any WD-40 in there like I recommended in steps 2 and 3 to loosen the shaft in the bearing. As a result, the bearing ripped out of the motor housing, still attached to the motor shaft.
Once I realized what had happened I had to re-set the bearing into the motor housing.
To do that I needed to pry back the metal retaining clip teeth that normally hold the bearing in place in the motor housing. Since there are large magnets on either side of the motor housing extra caution needed to be taken when using metal tools in there since the magnets chip easily. To help protect the magnets I wrapped a strip of rag around my needle nose pliers before using them to pry the teeth back.
After I got the bearing back into the housing I used a rag wrapped flat-head screw driver to jam the teeth back down to hold the bearing in place.
Before replacing the cap and newly lubed-up bearing on the motor, I used WD-40 on a rag to gently clean and protect the motor parts. Over the years a lot of metal shavings have accumulated inside the motor as well as a bit of rust on the motor wire fixtures. Be careful not to douse the motor wires in WD-40.
Replacing the cap took a couple tries because the magnets on the sides make it difficult to get the motor shaft lined up and into the bearing hole. Once you get it though you're pretty much there.
I used a hammer and flat-head screwdriver to pound the metal tabs back into place. Just follow the instructions in reverse to replace the motor.