Blue bottle. What's it for?

[George & Maria Tur <getur@bellatlantic.net>]

Sitting in the son's 87 5ktqs with the drivers door open trying to pin
down where a new buzzing sound was coming from and I noticed an odd
shaped, looked like three balls stacked on top of each other, blue
bottle/container deep inside the door jamb. It has a hose coming into it
and it looks like it's made of fairly dense plastic. I took a look
through the Bentley but the closes thing I could find was a vacuum
bottle that is part of the egr system for kh engine model cars. This car
has the mc engine so I'm at a loss as to what it is. Anyone have any
idea as to what it could be? Just curiousity on my part.

George

p.s. The new buzzing noise was from the electric engine fan. It has
never made that noise before so I guess that's going to go soon now. The
car likes us it gives a warning now.