Your car's windscreen is far more than just a piece of glass to keep the wind and rain out.
- A clean, clear windscreen is essential for good vision
- A bonded windscreen is an integral part of the vehicle body, contributing towards strength and stiffness
You can improve vision a lot, particularly when the sun is low in the sky, by making sure that your windscreen is clean, inside and outside.
- Even if you're not a smoker a hazy film will build up on the inside of the glass
- Scratches, abrasions and chips on the outside can make dazzle from the sun worse too
- New blades clear the screen more effectively and help reduce the dazzling effect of the sun – try to renew them once a year
- Keep the screen-wash topped up using a good quality screen-wash additive to help clean the screen all year round as well as reduce freezing in cold weather
Stone chips and cracks
Depending on its size and position, a chip on your windscreen can be a distraction or even impair vision.
Damage of up to 40mm across can sometimes be repaired, depending on where in the screen it is situated.
- If the damage is right in front of you – in the area known as the 'A zone' – only damage up to 10mm (slightly less than the size of a 5 pence coin) can be repaired
- Repair involves cleaning and drying the damaged area and filling it with a clear resin with similar optical properties to glass
- The damage won't completely disappear but the repaired area will be much less visible and have a smooth surface
- If ignored, small chips can grow and become irreparable. Secondary cracks can form through the combined effect of heat, moisture, frost, dirt and vibration
- Any dirt or moisture getting into the chip will make it more difficult to produce a visually acceptable repair so it's important to act quickly
The MOT test
Depending on where it’s located, some windscreen damage will result in an MOT failure if not attended to.
The screen’s divided into two areas for the MOT.
- Damage larger than 10mm across will normally result in a failure if it’s in the ‘A-zone’, a 290mm wide band centred on the steering column and bounded top and bottom by the windscreen wiper swept area
- Damage larger than 40mm across will normally result in failure anywhere else on the windscreen
Your car can fail the MOT if a wiper blade is insecure, missing, or in such a condition that it doesn't clear the windscreen effectively to give you an adequate view of the road (through the windscreen) to the left and right sides of the vehicle, as well as to the front.
Wipers that judder, make a noise, leave bands of rain or unwashed margins should be replaced.
If you'd like some further reading, here's some extra advice on how to keep a clear windscreen.
14 February 2017