I have 2008 XLT crew 4X4. I noticed two weeks ago a small spot on top of the passenger side mirror. Now the top and side of mirror is melted, also the wiper arm where it attaches to the wiper blade and the vents at the bottom of the windshield have spots. The plastic piece at the bottom of the windshield is warped and is turning white. Engine has never run hot, it's never been hot in the cab and we've never smelled anything hot. Under the hood the computer case attaches to the firewall in that area and there is no sign of melting on it. Service dept at dealership has never seen anything like it, it's still there now. They called Ford hotline who said only would melt with heat in excess of 170 degrees.

 

my guess is a kid with a magnifying glass got bored where do you park the truck?

 

In the drive which has a slope. A kid would need a latter and i'm home during the day so ruled that out. I thought about sun reflecting from a window but that doesn't seem possible. I also discussed this with the service dept and they agree from the angle of the deformed plastic near the windshield it must be heat coming from the engine compartment.

 

check for loose wires spark plugs and for exhaust leaks? that is strange pop the hood and see if theres something arcing as well that can melt plastic too but somethings not right for sure.

 

Thanks for trying! I'll wait and see what the dealer decides tomorrow.

 

You may be surprised by how hot reflected sun light off of windows may get. I had a construction project in the past where the artificial turf we installed was melting for no apparent reason. It was later determined that the window system on the adjacent building reflecting sun light was the culprit. I forget the temperatures that were later taken by the landscape contractor who was pleading his case but the numbers were unbelievable.

 

Those reflective windows do melt vinyl siding on nearby homes.

 

I found some info about windows melting siding, it seems that is possible. If it was just the mirror I would probably say that was it but the way the vents at the base of the windshield looks it appears to be coming from under the hood.

 

We have the same issue. Brand new F150. Bought in June. Started noticing the warping as early as August. Not only is the mirror warped and pulling away from the truck but the trim panel between the doors are warping as well. The panels are held on with double stick tape (that in itself is ridiculous for an almost $50,000 vehicle!).
Galpin Ford and Ford, Michigan have denied the responsibility for repair. Truck has 3300 miles - yes, that's correct, 3300 miles.
Tell me in what universe this makes sense????

Also - has only been parked in our driveway and we do not have "high efficiency windows" or "reflective windows" in our house!

 

This may sound crazy,
Does your Truck have the Heated Mirrors?
May have a short somewhere.
I know, it isn't the problem?