Ever see puckering on windshield cowling?

Flycaster

New member
While cleaning my 2005 Z4 (a garage queen with 16K miles) yesterday in the the SoFL heat (not really hot yet, but about 82 degrees), I noticed that the plastic cowling that sits over the bottom of the windshield was buckling. That is, it was puckering up off the windshield at about 4-5 different spots; otherwise, it was flush with the windshield. However, that night, all was flush. Anyone notice this on their cars? Think it is a defect worth taking to the dealer (I'm still under warranty) or does it have something to do with the plastic and the windshield expanding/contracting at digfferent rates?
 
Yes, it sounds like a difference in the coefficient of expansion. By any chance did you back it out of a cool garage into the sun? In that case the black cowling, with its lower thermal mass, was probably absorbing a lot of sun energy and expanding, while the metal and glass parts were not (as fast). If it all went back to normal later, I think you're good. Worth talking to the dealer about tho, just in case it's a known problem and they changed some adhesive or fastener.
 
Setec Astronomy said:
Yes, it sounds like a difference in the coefficient of expansion. By any chance did you back it out of a cool garage into the sun? In that case the black cowling, with its lower thermal mass, was probably absorbing a lot of sun energy and expanding, while the metal and glass parts were not (as fast). If it all went back to normal later, I think you're good. Worth talking to the dealer about tho, just in case it's a known problem and they changed some adhesive or fastener.



Yep, from garage into sun. Cowling is now tight fittting. I don't believe that they use any adhesives between the cowling and the windshield; probably a pressure fit secured at the base. I will call my SA at BMW to see what she has to say.
 
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