124 300TD air-blower squirrel cage squeaks
 

Blower squeaks (should attach a Tom&Ray-mp3 of the squeal) intermittently and the sound changes, sometime it is quiet. Sound is most obvious at low fan setting. This "fan/cage" is a replacement from a friend's parts car. This car's previous blower cage thup-thup-thupped - with blades hitting the edge of the lower blower container. This cage ran true and did not hit when I replaced/tested it. I've replaced these blower cages in two 124s. It is a do-able PITA. And I'm writing to ask if anyone has tried alternative strategies.

Dealer says probably not a bearing issue. He quietly advocated drilling 1/8" holes ar the edges of the housing top (without pulling the monoblade) to aim silicone spray (low VOC not WD40) at the outer edges of the fan blade, then RTV the holes. Is he nuts? Or am I nuts for not trying it in a heartbeat?

PS A/C works, not an issue with the vac mods...this squeal also happens with the next setting over

By the way - has anyone got info on a MORE VARIABLE speed fan? the original 124 has 2 settings: High-full blast-noisy, and Low-light-slow. Plus there is the AUTO setting which seems to mean HIGH-all the time. Is there an upgrade to a more variable-speed fan?

IMHO the squeal is not related to the blades, I think it's the blower motor bearings. Mine is starting to squeal, particularly when turning the car one direction. I think you have to lube the motor bearings, which I doubt you can do by spraying silicone. I believe others have used ATF with success.

In any case I don't see a downside to trying what the dealer has suggested, a couple small holes plugged with RTV won't hurt anything.

If you could come up with a drop-in replacement gizmo for variable speed on that blower motor you'd have a bunch of us 124 owners beating down your door to buy it! (if your fan never seems to slow on auto, try aiming the right center vent's flow up towards the inlet grating on the overhead console. Putting a direct flow of temperature controlled air on that sensing grate makes my system somewhat more sensitive to cabin air temp)

Rgds,
Chris W.
'95 E300D, 343K

Here are some ideas for finer control of the blower -

http://www.peachparts.com/shopforum/diesel-discussion/270584-w124-manual-blower-control-diy.html

Again, being a feedback system, the ACC might mess with air temperature if you override blower control. Maybe that's a good thing.

Does the squeaking coincide with hard turns?

Sixto
87 300D

Hey guys, thanks for the feedback. Sixto, the squeal does not sound turn related. Sometimes it is quiet, other times it is fairly constantly making a variety of low-volume high-pitched squeaks on Low that are drowned out if running on Max or Auto. Chris, I'll try aiming the vent up to see if that gives me some mid range, Thanks. Sixto, did you ever get that W140 mod? And would you guys think that a turn-influenced squeak would indicate a possibly loose blower center clamp that is allowing the cage(s) to rub (contact the housing) as a result of the spinning gyro-torque "resisting" the turn? Mine is not doing that. And it spun freely and smoothly when I replaced it. Maybe I'll just turn up the radio...

I'm not enough of a sparky to figure out resistor specs and such. I'm not enough of a craftsman to fabricate a control thumbwheel connected to rheostats of pots. I took apart an early 140 PBU but the thumbwheel doesn't turn a mechanical device like I envision.

Besides spinning freely, check for axial play in the motor.

Squeaking in turns can indicate worn motor bearings. I experienced a metal-on-metal squeal as you described, not a plastic cage on plastic housing scuffing. The replacement motor had a wobbly cage that scuffed. I trimmed the housing to correct that.

Sixto
87 300D

Have you oiled the bearings on a squeaking blower motor? I remember oiling and hand spinning and oiling again, on a previous 124's blower motor, and the cage never felt like it was spinning more freely. But I can't remember if squealing was and issue to begin with (except why else would I have pulled it? As I recollect I'd bought a replacement from fastlane and it did not fit - the motor was wider than mine, so after all that re-oiling I think I reinstalled it) But that car didn't have AC so the blower was not usually on Low. I'm not sure going through all the effort of removing the monoblade to oil the motor is worth it, if it is just going to last another year or so... I'm pretty sure you can't get at the bearings to repack them... I think you're right about the metal/metal squeal not being plastic housing related.

John
87 300TD 308,000