Grinding noise from heater / blower

[leicesterboy15]

I've done a search but I can't find anything specific to my problem unless you guys can point me to a post?

My problem is when I use the heater I get a faint grinding noise from the dash, its not the vents opening up, its coming from behind the centre of the dash. Sometimes when I turn the heater on its fine and then it just cuts out randomly, if its on low - med there is a faint noise and it gets more intense as you turn the wheel up. Its also inconsistent, sometimes it cuts out completely other times its a mixture of grinding and air with the grinding getting worse as the air reduces and vice versa, then it either corrects itself or just cuts out completely. Other times it doesn't turn on at all and as I turn the wheel up the grinding gets louder, as soon as you put it on full its fine.

If I move it from full to a lower setting it works fine but sometimes it will cut out after a few miles and the problem comes back. It always works properly on full. I can also smell coolant but I do have a leak in the engine bay somewhere (I think its from the pump itself (which is new) or the pipe to the back of the engine). When I have given it some it smells worse.

I can't hear the grinding from the engine bay as the engine is too damn loud but when the engine is off the blower seems to work fine.

I've found loads of posts tackling heater core leaks and coolant smell but none mention the grinding, it sounds like something is trying to rotate but is worn out and will break if it grinds for too long so I'm not sure its a leak but more likely that the core has had it. Has anyone experienced this or is there a way I can test this further without removing the whole dash? It started happening after the cold weather, it is the auto climate system with the three wheels and not the rotary dials.

[russiankid]

Sounds like the blower motor to me.

[stx133]

the blower motor has carbon brushes, these wear out and can cause noise, other it can be contact on the fan impellor when the bearings on the blower motor wear and axial movement of the shaft. either case, replace motor. you can pull it out - access from engine bay behind water reservoir - and check / clean.

[leicesterboy15]

Excellent, thanks guys, its great news that I don't need to access the core just yet!

[Bo525i]

I took my old blowers out earlier today, due to it finally being completely stuck after 2-3 months of grinding and chirping loudly, turned out that the brushes and coals were worn down totally and it had been grinding raw metal for who knows how long.. So a replacement was needed, thank God for the nearby scrapyard!

Its quite easy, but the frontplate has 5 screws where the lower middle one can be a biatch to get to.. You need to loosen your watervalve too and move it aside, to get to the lower left screw. Once you´re in there and start removing plastic be very very careful, my blowermotor cover was brittle and disintegrated when I was removing it.. The rest is quite obvious and relatively easy, mind the clip that holds the blowers, its tight use a hook or something similar.

[leicesterboy15]

Thanks! So I take it you do all this from the engine bay and all will be revealed once I remove the expansion tank?

[Bo525i]

Yea that, the cableholder, and frontplate (bulkhead splash shield) behind it, then you´re in! I forgot to tell you that the blowercover is attached with 2 small metal clips @ the bottom.. Its important that you remove them to slide the cover upwards.

Here´s some good pics of how things are attached, different model car, blower spring and blower but it gives you the general idea: http://www.exx.se/maintenance/windshield_wiper_console_change/index_ii.shtml

[BennyM]

Yes, it's from the engine bay, but generally there's a lot of crap in the way, at least with the M50 and I assume M60, so it's pretty time consuming. It helps to remove the plastic engine covers on top. For those of you with an M50, it would be the plastic shield that covers the fuel rail. Also, the actual blower motor has two hamster wheel type things that are very brittle plastic and I always had to deform them a bit to fit the unit past all the obstacles. Don't try to shove the whole thing in at once. Work on getting one hamster wheel in at a time. I've replaced the blower about three times now, I think. And I don't look forward to having to do it again. I highly recommend buying a new blower instead of a junk yard one, so you only have to do it once. The used ones I found usually had very little lif left in them.


Thanks! So I take it you do all this from the engine bay and all will be revealed once I remove the expansion tank?

[leicesterboy15]

Thanks guys! The blower motor looks huge! I remember when I rebuilt the air intake with a new pcv plate there is very little room around the expansion tank area. I think I'll wait for the weather to improve a bit first. Anything else worth doing while I'm in there? Am I right in thinking the blower motor is the same regardless of aircon system and model?

[Kibokojoe]

It probably the bushings. When these give out the squirrel cage can move around and hits the cover.

[Bo525i]

I highly recommend buying a new blower instead of a junk yard on

Yea, probably a good idea unless you find a really good one like I did with 3/4 of bushes/coals left, seems like its a relatively new replacement one from the bashed up donorcar :)

[Ross]

http://www.e32-schrauber.de/bmw/daten/ihka/+blower_motor_write_up.pdf

[Kibokojoe]

Very nice. I download the pdf and stored it for future reference

[leicesterboy15]

Thanks! Thats very useful information! I might have to be this route if I can't get a BMW one