Rear demister cause rear window to shatter?

[gendi]

good morning, well not really but anyway

a mate was driving my car this morning and said he turn the rear demister on and then the rear window (rear windscree) shattered, has this ever happened to anyone or is he telling me a story?

[OzJD]

Sounds like a story. I've never heard anything like it.
Then again, you should have some trust in your mates.

I would imagine that if it was too cold, it's a little possible, but i've had it on at pretty cold temps (isn't that what it's for).

Also possible something flicked up as he turned it on?

[hako]

I've heard of that happening before...rare but possible. Bit of bad luck - maybe you can claim on insurance?
Do a GOOGLE for 'heated window shattering' and you'll find instances.

[VSIIBerlinaL67]

happened to me when i was driving my grandparents xf, turned demister on, minute later bang!

[Kirbs]

Sounds reasonable. Was he driving in cold? Same thing happened to my dads patrol, But it just cracked.

[OzJD]

Well there you go, not so uncommon, Have a little faith in ya mates

[Cobez]

No, it's no bullshit, if a windscreen has a chip in it, then it goes from one temperature extreme to another, that crack can rapidly spread (shattering).

Hence why it's a good idea to get all windscreen chips fixed when they are small.

[hako]

The rear screens are tempered glass which is a lot more brittle than the front laminated windscreens.

[gendi]

thanks for the input guys rang a few window repair places and they said its pretty common problem.

[vsl67]

As cobez said they may have a small chip or crack moisture gets in them,(when water heats up it exspands) so when you hit the rear window heater ,they shatter