I have never seen anything like this. The A/C box that hold the heater core, fan, etc is just deteriorating. Pieces of it are just falling off it. Needless to say the fan doesn't actually blow much air into the cabin of the car even on full speed lol. Is this a common problem? The reason I ask is because if it is common it will be hard to find a replacement since they are not carried by the dealer anymore and I will have to find a salvaged one.

Can't say that I've heard of it happening. I guess if the engine bay was subjected to a lot of heat the plastic may have become more brittle then it normally would have.

This happened to me also - the bottom 1/3 of the box basically became brittle and fell out. I rebuilt it with fiberglass cloth and bondo - its been over a year and its holding. I could probably take a picture of it later, if anybody wants a few laughs...

heh the one I have dosent have enough left of it to rebuild lol

X4.
Mine did the same thing

My 96 has the same problem Dealer told me I could get new one for i think about $215.00. I'm not sure how bad of a job to cnange it. It started a few years ago. didn't seem too bad until blower moter started squeeling like a stuck pig. I went to give a little tap to the blower cover and the cover disintegrated. New cover $75,00, cooling hose $15.00 Blower motor $60.00. Priced out I blower module cover tried to get labour time value to replace it the service coordinator could not tell me. Service manual for 98 closest repair given is to replace evaporator core. Still have heat yet as insulation is still intact. i will just have to decide what i want to do.