Blower Motor (In Dash for A/C, Heat) Squeak/Noise Thread

[blackswan]

There are many threads with excellent contributions/photos and I thought it would be worthwhile to compile into one with as encompassing a title as possible.

In another thread I posted pictures of the fan I received from AutoZone, a VDO model:
http://www.camaro5.com/forums/showth...=250934&page=2

We've always assumed that the noise was coming from a "bushing" in the bottom of the motor (the part facing the interior of the car). However, I have disassembled the OEM motor and found that there are indeed (very common) 608 bearings top and bottom. Removing the seals on both I found that the top bearing (supporting the side of the shaft the squirrel cage plastic impeller mounts on, away from the interior of the car) was in good shape. The rear one, where the squeak seems to come from (the bottom of the motor where the power leads go in), was a bit gritty but still in good shape. Cleaning it and repacking (I used Shimano bearing grease used for bike hubs) restored smooth operation. It wasn't in that bad shape, certainly nothing I could see/feel that would explain the "tight/rough" feel of this motor when spun by hand, and probably doesn't explain the squeak either. However, there was a great deal of grit in and around this area from the brushes. It's entirely possible the grit (more of a very very fine dust) gets into the bearing, even if it's a sealed bearing design (608D, yet I can't find what the D designates, usually it's a Z or ZZ or other well know bearing type designation - maybe it's D for Dirty ). Both bearings were much drier than I would have expected, but perhaps they were only lubed with a light oil.

Looking at the brushes, they seem to have some grooving and one of them has pitting. I'm pretty sure THIS is where the squeak is coming from, not the bearing(s). This would also explain the tightness, as the brushes have this grooving and pitting and probably a good bit of drag, not helped by all the dust. This MAY explain why some people say their squeak goes away, which wouldn't happen with a bad bearing. If they use their fan more than others, the brushes might wear more and have less spring load (due to length shortening due to wear) over time. Assembling the motor with brushes not installed would show the motor free spins smoothly, quietly and much more freely.

What to do?

Unsure. I'm going to clean the brush ends and copper pick ups with 1000 grit or so and re-assemble and see how it feels. Since these are "tight" right from the factory perhaps the design is poor (too much spring tension in brushes), brushes aren't great and/or the copper pickup plates aren't polished or are supposed to have a coating, unsure.

[blackswan]

One thing that might be helpful, and very easy to do, is spray electronic cleaner into the hole in the side/bottom of the motor (which mates up with a vent in the plastic housing, which is interesting). You could clean the brushes and copper pretty easily that way. But be careful about getting cleaner near bearing, even if they are sealed fluid could seep into the bearing. Perhaps best to pull it the whole motor out and pack that area of the bearing with cloth or paper towels before spraying the contacts/brushes.

[rocknroll_jeph]

I am subscribing to this thread. On my car the squeaks have come and gone over the past year, and I have not been able to find a pattern as to when it is more likely to make noise, it seems random at this point.

[rwhxk3]

Mine does it at low speeds.

[sjmautoprod]

The D is for Double seals.

[blackswan]

You might be right, perhaps that's a new designation implying double seals. Typically, you'd see double letters, like ZZ, when there is a double seal/guard. Nice write up here: http://www.gizmology.net/bearings.htm

Originally Posted by sjmautoprod

The D is for Double seals.

Alas, it's not the bearings causing the noise. I wish it was actually, since repacking mine it's smooth as silk UNTIL... I reassemble with brushes fully engaged with commutator, then back where I started - drag and noise (but no squeak). I've confirmed the following noises are the brushes:

Squeak

"Motor noise" - best I can describe it, just the noise of typical electric motor though louder in these.

Ticking noise (other than something rubbing the fan).

[TooCool5]

Wow didn't know this was serviceable. Thought you had to cut it out with razor knife?

[Crash76]

I was wondering what that noise was ... Wierd ticking / squeak noise during my cruise last weekend ... It was random and annoying

[JacekPSUr1]

Subscribed!

[anglwngss]

subscribed

[Crowmag]

Thanks for sharing. My ticks eventually went away but I faintly heard it again a month ago.

[blackswan]

Originally Posted by Crowmag

Thanks for sharing. My ticks eventually went away but I faintly heard it again a month ago.

Does seem to come and go!

I'm going to see about a replacement motor and see what u can construct

[blackswan]

Originally Posted by TooCool5

Wow didn't know this was serviceable. Thought you had to cut it out with razor knife?

Mine was done once already by a dealer, so it was trivial to remove. I'm not sure I'd call it "serviceable" I had to bend many tabs on the motor's top bearing housing in order to remove it, I'm unsure I'll be able to reassemble with reliability but going to try to JB Weld it closed since I don't expect I'll be tearing it open again now that I know what's causing the squeak.

[HP Turbine]

mine would squeak low speed. It was most common when it was very cold out. I had mine replaced under warranty, but it didn't last long