02-01-2013, 08:35 AM
Humble E34 lover
Location: Asheboro, NC
Join Date: Dec 2008
Mein Auto: 1992 525i
Here's a long shot (well, maybe not so much). There is a very small fan that is part of the climate control unit (the unit with the three knobs for regulating temperature, fan speed and vent control). It is designed to draw air in the little slots on the panel and then over a sensor that tells the climate control what the air temperature in the cabin is. The fan is part of the unit itself and can be replaced, but it is easier to just get an entire climate control panel from a pick & pull. If this fan is on its way out, it may be making the noise.
Place your ear as close to the slots in the climate control panel as you can and see if the sound is emanating from there.
By the way, I have a complete spare climate control panel and a second climate control panel in parts. I do have the little fan of which I speak separately in this one. The complete unit doesn't look new and hopefully would function fine.
The history on that is that my climate control unit was acting rather wonky and the bulbs went out on it. I went to a pick and pull and got a panel. Then I looked at another junker and it had the second type of panel, and I didnít know which one mine had, so I snagged them both. I had to have the heater core replaced, so I gave my spare unit to my mechanic and he put in the spare. It works perfectly and there was no labor to install the new panel since he had to remove it anyway to replace my heater core
I kept the old one just to take apart and look at things, hence its state of disassembly which allows the fan motor to be immediately accessible.
There are at least two different units in the E34 series. You can tell the difference in the two by removing the unit and looking at the back of the unit at the actuator for the foot area vent slide. One style is cable operated (my 92 is) and the other is electronically operated (which is the complete unit that I still have).
Thus, I have the one that the foot vent control is controlled electronically. I would be happy to send it to you for cheaps (say $20 plus shipping). If you just need the fan, I will send it to you for just the cost of shipping.
So, see if that is where the noise is coming from. If it is the fan, then I can either send you just the tiny fan motor (if your unit uses a cable to control the foot vent) or the entire unit if yours is the one with the electronically controlled foot vent.
Just let me know if that's where the noise is cominig from and if I can help out with the parts.
Calypso Red 1992 525i with 183K miles
1991 735i - Sold
1992 525i - Sold
1995 325is - Sold
2000 528i - Sold