The windscreen leak is becoming ever more common due to the number of replaced windscreens now being fitted. I'm not sure what makes the smart windscreen harder to fit but it must be, I have heard and been contacted by countless people with a leaking windscreen.
Up until the 90's many cars would have the windscreen held in with a rubber seal. These were easy
to use and pretty much foolproof. However, with advances in manufacture they now have a massive
range of powerful sealants and the majority of manufacturers choose to bond (glue) the screen in.
So, whereas the rubber seals made contact at 3 points, bonding only makes 1. Bonding
was seen to be a better option due to speed and the fact that rubber seals can perish.
This is fine as long as the windscreen is clean, the aperture on the car is clean, the
bonding is applied correctly (evenly with a thick enough bead), the bonding is left to
cure long enough before the screen is replaced and that the screen is fitted properly.
In the factory, everything is as clean as it needs to be. The bonding agent is applied by
a robot and similarly, the windscreen is placed in by a robot. Not much to fault there.
The problem starts when the factory windscreen is damaged and has to be removed and replaced by some dirty greasy garage worker in a windscreen fitting centre. The windscreen they fit will probably be a non OEM one, it will have sat around in a warehouse for ages, the sealant will be applied by hand, very little cleaning will take place, no waiting for the sealant to cure and the the screen will be refitted by hand.
Why? because they want a quick turnaround and another cup of tea. The other reason being, despite rushing through the fitting, 99 out of 100 will be fine. That's ok unless you are the 1.
Lift up your carpets in both footwells and feel the foam backing for damp.
If you own a fortwo and the underside of the carpet is wet and the windscreen has been replaced,
there is a good chance that the leak is coming in from a poor seal around the windscreen.
Pin Pointing Leaks
Have a look at the leak finding guide here.
A leaking windscreen should be taken back to the fitter.
If it's the windscreen that came from the factory, check your insurance covers windscreen replacement, check that you can afford the excess (usually about £50), phone up your local windscreen replacement centre and tell them that your windscreen is broken and that you need
a replacement. Wait for them to get one in stock. Just as you are about to drive to the fitters,
smash the passenger side of the windscreen (so you can still drive it safely).
There you go, new windscreen with fitting warranty and (hopefully) a fixed leak, nice and cheap.
Isn't That Dishonest?
Yes, say 10 hail Mary's and repent your sins when you meet your God of choice.
Best Way To Smash The Screen?
The obvious choice is a brick, you can say that a lorry with double wheels flicked it up.
However, they will have seen this lie a lot. Obviously they will still do the job though.
By far the best way to do it is to use an automatic centre punch.
This makes the damage look indistinguishable from stone chip damage.
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