Expert tips: how to put screen wash in your car

Screen wash helps ensure you can see in low winter sun

Topping up your screen wash helps ensure you can see in low winter sun. (Picture © Prestone)

Car maintenance such as topping up screen wash isn’t everybody’s cup of tea. But there are some things drivers really should be able to do to ensure their cars are as roadworthy as possible. It’s quite a worry that a new survey shows that two thirds of drivers can’t check the oil level in their cars; 31 per cent don’t know how to check tyre pressures; and nearly a third don’t know how to fill their screen wash bottle. 

Filling up the screen wash is quick and easy and it could save your life. Being able to see ahead of you is one of the most important aspects of driving. The earlier you can spot a hazard, the more chance you have to react to it in a safe and appropriate manner. And in order to be able to guarantee that you can see in front of you there needs to be liquid – and preferably screen wash – in your car’s washer bottle.

Why screen wash?
Screen wash is available from motor retailers, garages and even some supermarkets and is designed specifically for the job of windscreen cleaning. You can get it pre-mixed or you can get a screen wash pod to easily add to water. You can find these pods at the Green Flag Shop.

It will help avoid the wiper blades smearing on the screen; it has water softener in it to keep the pipes and jets clean; and it’s formulated to clear road grime and insects. It also has anti-freeze in it so won’t turn to ice in very cold weather. And unlike washing up liquid it doesn’t have salt in it that can damage paintwork.

Screen wash can prevent windscreen washer bottles freezing on cold mornings

Screen wash can prevent windscreen washer bottles freezing on cold mornings. (Picture © Continental)

What does the washer bottle filler look like?
Washer bottles can be located anywhere under the bonnet. The easiest way to find yours is to look in your car’s handbook. The cap is frequently blue, although it might be black or even white. It’ll also be stamped with a graphic that shows the shape of a swept windscreen with water drops squirting up from the middle.

How much screen wash?
This depends on the time of year. The colder it is, the more screen wash you’ll need to prevent the liquid freezing in extreme cold. Each bottle of screen wash will detail the proportion of wash per litre of water, depending on the time of year.

How much do you put in?
Washer bottle capacities vary from car to car. They nearly always hold at least two litres of fluid but you should find their capacity in the handbook. Otherwise, the only thing to do is to mix up a couple of litres of screen wash with water in a clean bucket and pour it in, either using a jug or funnel, until it gets to the top of the filler pipe.

Green Flag's Nick Reid talks all about screen wash Nick Reid is a fellow of the Institute of the Motor Industry and head of transformation at Green Flag

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14 comments on “Expert tips: how to put screen wash in your car

  1. John Perfect 26/02/2016 3:32 PM

    Is it OK to mix different types of screenwash eg blue coloured screenwash with pink coloured screenwash?

    • James Mills 17/03/2016 3:11 PM

      In a word, yes. Should smell a treat too!

  2. Doug Barnes 12/06/2016 7:58 PM

    if you live near an airport, a little bit of Meths helps as well, Also improves icy weather behaviour, but pipes do need an occasional flush with plain water to keep them clear

    • wayne jones 12/12/2016 8:05 AM

      what has living near an airport got to do with it very confused

      • Ray Hoole 29/10/2017 2:10 PM

        If you live near an airport and you’re filling your wash bottle, you will have to wait for the plane to go over before you can hear your screenwash, trickling into the bottle, enjoy.

  3. Dave Ellis 02/03/2018 9:33 AM

    Not sure recommending supermarket screen wash is good advise, usually low quality clogging up washer jets and will require lower ratio in colder weather to avoid freezing

  4. Pete 04/03/2018 1:39 PM

    Seems to me pressure needs applying to the manufacturers for the capacity of washer bottles to be contained in hand books. Not difficult for them, surely. It is simple to do tho. Empty a 2.5ltr of a/f into a larger container that will hold 5 litres and top it up with water. Maintain a stock of that in the garage and start using it when you know the reservoir is about empty.

  5. Gary 16/07/2018 11:06 AM

    Water is empty our much screenwash do I put in got a fiesta one year old

    • nobby 09/02/2019 8:08 PM

      hello, my fiesta is an old 2001 model and holds about half a gallon ( 2.5 ltrs)

  6. Ronald Meers 23/01/2019 10:41 PM

    When filling your screen wash does that include the back windscreen as well

    • Col 02/04/2019 12:33 PM

      Yes, they are fed from the same place

  7. D Macqueen 11/10/2019 11:49 AM

    I’m confused. If all you do is top up by adding some winter-strength screenwash to what’s already left in the reservoir from summer, how can it make an appreciable difference in terms of winter performance? Shouldn’t you drain the reservoir completely and then refill with a solution appropriate to the time of year? And if so, how would I go about draining the reservoir? I’m ignorant, me.

    • Hobanoba 20/01/2020 8:48 AM

      It will get diluted, best anticipate the cold climate and start using the winter formula before you actually need it – or use it all year round.

  8. Tony Payne 24/11/2019 1:28 PM

    I was wondering whether it was better to dilute the screenwash with tap water or distilled water, especially if the tap water is fairly hard.
    We have a condensing tumble dryer, so have a ready supply of distilled water. Didn’t want to use it though if it was not recommended.

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