Recently, I bought a 1997 850 T5 with 93k miles, and it's been great. Except for the ABS ECU, which seems to be going (but that's for another time!). However, I was driving along, and then with both controls down to their lowest setting, and the AC on, smoke/steam/vapor began to flow out of my vents! I'm pretty confused to why this would happen. Either way, the smoke was odorless, and was white.

This happened twice yesterday. Usually it happens when I turn the A/C off, and back on again in a few minutes.

Thinking about this, I came to the following conclusion(s) of what it could be:

1. Heater Matrix. I hear that coolent leaks will cause something like this. However, this happened when I had the A/C on, and it on it's lowest setting. I will continue to monitor my coolent for leaks. I don't believe there has been though, and my temps have been stable.

2. Evaporator. Somehow that doesn't make sense, because I thought that it would just not have cold air come out of the vents. It does cycle a lot, I think. I'm going to take it in for a recharge before I leave for school.

3. Pollen Filter. It's really dirty and needs a clean. I'm going to try this first.

Also, after doing a couple tests on when this happened, the Climate Control Unit falted. However, it was a 20 second blink type fault, and from what I looked up, this could be minor. It is quite coincentdental. I would appreciate any help on this; I'm getting nervous about the reliability of the car!