Is there a cricket living in your car?
by Bruce Mock
motorsport
Rocky Mountain Chapter
BMW CCA - June 1999
I remember very vividly the last E-28 we owned. It was a great car and we've missed it ever since the day we let it go. Recently an opportunity to purchase another e-28 came along and, as the old saying goes, "I just couldn't pass it up." This makes bimmer number three and my bride of fifteen years says this car thing of mine is a diagnosable mental illness. I just remind her that everyone needs to have one vice, and that it's OK since I don't chase other women or drink, or smoke, or do drugs or...or...or...(I don't quite understand why I don't seem to get as much mileage out of saying this as I think I should!)
I received some nice feedback on the article dealing with fixing headrests so I thought I would share some information on another common e-12 and e-28 malady ---that of squeaky heater blower motor fan bearings. If your heater fan sounds like a large cricket has taken up residence in your car when the motor is run at slow speed, take heart because there is a cure.
Bearings? Did I say bearings? Actually if BMW had used bearings instead of cheapie oillite bushings we wouldn't be having this conversation. Ah well....The fan is located directly aft of the firewall at the base of the windshield. Raise the hood and cut off all the zip-ties holding various cables to the firewall. Remove the eight or so small hex-head bolts located around the perimeter of the access panel. Slip this panel out and set it aside.
The motor is now in plain view. The motor is held in place by a large spring clip that passes around the body of the motor. Unhook the clip and electrical connector and the motor will come out. Remove the squirrel-cages from the ends of the motor shaft. Be careful not to damage the retainer clips or break the plastic squirrel cages. Mark the cages "left" and "right" for later reference. Next grind the retaining tabs off of one side of the motor. Disassemble the motor and remove the motor brushes. You may want to replace the brushes if they seem excessively worn. It is possible that the squeaking noise is coming from the brushes themselves. If the exact size brushes are not available, buy the next closest size and file them down for an exact fit. Also, you will need to solder the brushes in.
Clean up the motor using some kind of electronics parts cleaner. Now polish the shaft using fine emery paper. Finally, remove the spring clips that retain the old oillite bushings.
Now you are ready to hunt down some nice ball bearings to replace those worn oillites. Seek out a hobby shop that deals in Radio Control cars. They should have a good selection of ball bearings that will fit in place of the oillites. The diameter of the motor shaft is 6mm so you will need a 6mmX (I think) 13 mm bearing. Take the motor parts with you to the hobby shop to be sure.
Upon reinstallation of all the motor parts you will notice that the factory clips provide enough tension to retain the bearings in their motor end caps. Now, remember those tabs you ground off earlier? You will need to put a couple of spot welds or equivalent exactly where the tabs used to be. Find a friend who has a mig welder, go to an exhaust shop for help or as a last resort you may even be able to use some JB-Weld to hold a make-shift tab in place.
Reinstall the motor in the car and try it to make sure it runs before reassembling the cowling. Worst case scenario, you will need to buy a new motor assembly from the dealer. Even at that, you will still have saved yourself the cost of the labor for installation. Come this fall when the snowflakes fly and the windshield begins to fog, you'll have long since bid the chirping cricket goodbye!
This month's Quick Tip: If you have a yellowish-brownish stuff (dried cosmoline) that seems to be baked onto various aluminum engine parts, this stuff can be removed using K-Mart brand (no I don't usually buy car parts at K-Mart!) "Super K3 Paint Remover." Dab the stuff on with an old brush and the dried cosmoline will wither away. Be sure to keep the remover off any rubber parts. Follow up using a small spatula or scraper to remove the leftover goo. Remove any remaining residue with a bit of warm soapy water. Now you are ready for the next club Concours competition!