How to Dilute Screen Wash Correctly

A well-maintained vehicle requires regular topping up of important fluids such as brake fluid, coolant, and screen wash. Screen wash comes in a few different forms, and in some cases it may need diluting before it can be used.

In this guide, we’ll explore what types of screen wash there are, what they’re used for, and how to use them – including how to dilute it properly.

Do You Dilute Concentrated Screen Wash?

Screen wash marked as ‘concentrated’ should be diluted with water before it is put into your car’s reservoir.

The level of dilution is related to the time of year that it should be used and by extension the temperature that it will operate at. Summer screen wash, naturally, won’t be rated for use at -10°c, so it’s best to use a specifically designed winter formula.

Prestone Concentrated Screen Wash Products

To cut down on plastic waste, Prestone developed Super Concentrated screen wash, which works the same as regular concentrated screen wash while saving over 75% of the plastic.

Prestone Eco Refill Summer Screen Wash (Super Concentrated)

This Super Concentrated formula of Summer Screen Wash produces up to 5L of screen wash from just 500ml of concentrate. The screen wash still provides the same level of performance as the pre-mixed options but cuts down on plastic waste.

Prestone Eco Refill Winter Screen Wash (Super Concentrated)

Prestone’s Super Concentrated Winter Screen Wash is specially formulated to make light work of ice, salt and grim that can impair visibility during the colder months of the year. The screen wash melts ice down to -10°C.

Prestone Extreme Performance Screen Wash (Concentrated)

If you find yourself in extreme conditions where -10°C would be considered warm, then you must opt for Prestone’s Extreme Performance Screen Wash. This concentrated screen wash can either be diluted or bought as a ready-to-use formula depending on which variant suits your needs. The Extreme solution melts ice up to -18°C, so it really is designed to Excel in Extremes.

How to Dilute Prestone Screen Wash

Screen wash is sold in either ready-to-use or concentrated solutions. Ready-to-use solutions should be poured straight into the screen wash reservoir to achieve the best results, whereas concentrated solutions require mixing with water to give the best results.

Extreme Performance Screen Wash

Prestone’s Extreme Performance Screen Wash offers excellent versatility, being capable of washing away grime in high heat or extreme cold depending on the dilution.

  • Winter ratio: Use neat (do not dilute)
  • Autumn/spring ratio: 1 part screen wash, 9 parts water
  • Summer ratio: 1 part screen wash, 19 parts water

For example, in spring, if your reservoir is 5L, you would use 500ml of screen wash with 4.5L of water to achieve the best results.

Prestone Eco Refill Summer Screen Wash (Super Concentrated)

Our summer screen wash excels in the warmer months, offering exceptional clarity and ease of use. Because of its super-concentrated formula, the Eco Refill is superb at removing dirt and grime leaving a streak-free finish.

This screen wash should be used at a 1:9 ratio, with 500ml of concentrate making 5L of screen wash.

Prestone Eco Refill Winter Screenwash (Super Concentrated)

Our winter screen wash is specially designed for use in the colder months of the year, coping magnificently at temperatures as low as -10°C.

In order to use it, simply mix 500ml with 4.5L of water to make 5L of water (1:9 ratio).

Screen Wash FAQs

Do I need to dilute screen wash in winter?

Whether you need to dilute your screen wash in winter is entirely dependent on the screen wash you’re using. For advice on how to use your screen wash you should always check the manufacturer’s instructions.

What happens if you don’t dilute concentrated screen wash?

Not diluting your concentrated screen wash isn’t the end of the world, but it could lead to a build-up of residue that could obscure visibility if used for prolonged periods.

If you’ve got any more questions about screen wash, check out our 5 Screen Wash Myths — Busted guide.

By making informed decisions on which screen wash is best for you, you can make the road a safer environment for yourself and for other drivers by ensuring that your windscreen is frost-free and crystal clear. For more tips and help, check out our handy advice hub.