Loud squealing from glovebox area

[Master7122]

So recently my truck started making this squealing noise behind the glovebox. It only happens when the heat is on, once i turn it off it’ll stop. I turn the heat back on and no squeal until about 5-10 mins and then it starts making the nose again. Wondering if anyone knew what this could be before i start taking the dash all apart. Thanks in advance 

[Pete M]

sounds like the fan is going south.   

[Eagle]

Agreed. The ventilator fan runs in bronze bushings, not roller bearings. If your's isn't too far gone, you can drible a couple of drops of oil into it. On the end with the squirrel cage, ideally remove the impeller and drop the oil on the shaft (not too much), then replace the impeller. On the other end, drill a small home in the center of the bump where the end of the shaft is, drop in a bit of oil, then put a piece of tape over the hole.

[DirtyComanche]

You can take the fan motors apart and scotchbrite the bushings and put silicone grease or something like that on them instead of drilling anything.  You just have to be careful when you put it back together to not mash the brushes.  At least I've been able to do it on several of them.  Often you can bring a dead fan motor back to life by cleaning up the commutator and brushes.

[gogmorgo]

While we're at it it should be mentioned that the fan comes out from the engine bay side of the firewall, not through the dash. Don't tear your dash apart looking for it.

 

You may have a washer fluid bottle or coolant surge tank or something in the way, depending on the model (the above is a '91 if you're thinking it looks odd) but that cylindrical bit in the middle of the circle in the centre of the photo is the blower motor assembly. I think there's only three bolts around the outer edge of it holding it against the firewall. When you pull it off not to damage the drain tube, and remember to put it back on when you reassemble. If you opt for a new fan it should have the hole for it, remember it hoes down.

When mine started making noise I shot it full of electrical cleaner a few times then put a bunch of aerosol grease onto the shaft as close as I could get to the bushings. It quieted it down and seemingly improved airflow a bit after that, but after six months or so it started making noise again. Never bothered doing anything about it though, I've got a decent used motor sitting on the shelf waiting to go in if it gets real bad... Usually just flipping the fan off and on quiets down the bushings for at least a little bit. 

[Master7122]

Thanks everyone! I’m gonna take the blower motor out and attempt to rebuild/oil everything. I’ll have one on stand by at the parts store just in case