One last 300M problem

One last item has turned up on my 300M. I had previously complained to my
dealer that once in a while when you turned off the car, a screech came from
under the hood. In other words. after the engine is off there is a 2 or 3
second screach. Of course Chysler could not find a problem. Any ideas? I
am wondering if it could be some kind of pressure build up in the ac system
causing a problem when the car is suddenly turned off. It just happened
twice on me but now I cannot duplicate. It seems more likely when the car
hasn't been used for a while and is used for a very short time.

 

I have isolated the problem to occuring when the car is turned off while the
auto climate control is still in recycle air mode. If it is in fresh air
mode there is no noise.

 

I ran diagnostics on the auto climate control and it checked out OK but made
the sound once so it had nothing to do with turning the car off except for
the recirculation door moving. I exercised the door several times with the
button and that solved the problem at least for now.

 

I should ask, is there any way to lubricate the mechanism that moves when
you hit the recirculation button on a 99 300M?