Screen wash additives not only keep the windscreen clean during foul weather, they also prevent the washer system freezing in cold weather - which is when you are likely to need it most. Don't top up using plain water as the screen wash will become too diluted, and will freeze during cold weather.

1 Locate the windscreen/tailgate/headlight washer fluid reservoir, open the cap.

2 When topping up the reservoir a screenwash additive should be added in the quantities recommended on the bottle.