Body Expansion?

When traveling during cold weather (around 30degrees F) in my 55,000 mile Prius a loud cracking sound as if a rock has hit a window will occur a couple of times enroute. This is a horrific, frightening noise that occurs when the interior is warming up, about 10-15 minutes into the trip. Is the sudden crack the result of body expansion or a more sinister occurance? Is there anything to be done about it? Will it result in metal fatigue and cause me to fall from the sky? wstben

I've never heard of something like that before with the Prius, or any other car for that matter.

This happens to me as well, although I haven't paid so much attention to when it happens.

PA P

I would discount an engine problem as it only occurs when cold weather. Sounds like an expansion of something in your heating system maybe on some kind of plastic connection that pops when it finally warms enough. Just a guess though.

Can you narrow it to a particular area? Under your dash maybe?

Does it only happen when the defroster is on. Or, does it occur when only floor heating is on? Or possibly the rear defroster? It might help to narrow it down.

My experience is the same as wstben described-- it sounds as though a stone hit the windshield. That is also where the sound seems to come from.

PA P

Does it occur when the heating system changes from recirc to normal? I have heard of people complaining of a noise attributed to the opening and closing of the "door" that controls the recirc feature.

What about the fit of the dash near the winshield. Heated it expanded and pops as what ever it was caught on releases. Just a thought.