Frequently asked questions / Windscreen washer fluid

What is windscreen washer fluid?

The most widely used high-quality products of this type are a mixture of denatured alcohol and special detergents (emulsifiers), lubricating components, colourants and fragrance components. 

Where is it used?

Windscreen washer fluid is poured into a tank and supplied to the car windscreen wipers. It is used to clean car windscreens. As it contains active detergents, the washer fluid quickly and easily removes all dirt that reduces visibility, such as insect debris, dust, etc.

Does using plain water as a windscreen washer fluid cause any problems?

Yes, it does, and the problems are the following:

- Water cannot remove organic impurities (flies, butterflies and other insects) in a quick and easy way. As they are squashed against the windscreen visibility through it gets deteriorated

- Water freezes at 0°C and the process involves volume expansion which may result in cracking of the fluid storage tank

- Depending on its composition, water can be hard (has mineral content) or soft (low concentration of minerals). High hardness in water causes the formation of deposits (scale) on surfaces, and clogging.

Are there “fake” products in the market?

It is worth noting that every product of dubious origin may pose risks. A well known fact is that alcohols are included as a main component in the manufacture of washer fluids. Most popular are ethanol or isopropanol. Unacceptable and very dangerous is the use of methanol. Methanol intake has severe effects on the human body. Initially, headache, nausea and vomiting occur, followed by seizures and loss of vision. Methanol is an important ingredient in many products for industrial use, however, its presence in products that are expected to come into contact with, and have effect on human body is inadmissible. If present in windscreen washer fluid, its vapours reach the passenger compartment and during a long drive their effect is harmful and dangerous.   

Some products are of unknown origin but with a very pleasant fragrance that masks the harmful ingredient and, of course, have a very good price.

What is methanol?

Methyl alcohol or methanol is a colourless toxic liquid obtained by dry distillation of wood or by oxidation of methane. Methanol is banned as an ingredient in the composition of liquid household chemicals pursuant to Ordinance No. 35 of September 1, 1995 of the Health Ministry.

Why do problems occur with car paint and wiper blades?

The problems are due to incompatibilities and aggressive components in the washer fluid that have a corrosive effect on wiper blades rubber and car paint. 

To ensure compatibility, tests are carried out according to established methods. The winter windscreen washer fluid Prista has passed successfully the compatibility tests for rubber gaskets and materials and for impact on paint coatings. The tests were conducted in Germany according to internationally established methods.

Compatibility with water

Another test that is frequently ignored is for compatibility with water.  Strange as it may sound, often the components used are incompatible with different water hardness.  After mixing with water, insoluble substances form in the storage tank. They precipitate or float on the surface and clog the nozzles over time, thus deteriorating the spraying and screen cleaning possibility of the system.

Are there different types of washer fluid according to the season?

Yes. Washer fluid is available in winter and summer use formulations. Furthermore, the product may be a concentrated liquid that requires dilution in a certain ratio, or a ready-to-use washer fluid. 

BEFORE FILLING the storage tank, make sure you are using the correct fluid for the season. The storage tank must not be filled with products intended for other uses (such as antifreeze, because it does not freeze).

For example:

- The winter windscreen washer fluid Prista is diluted with water in a 1:3 ratio to achieve a freezing temperature of minus 20 °C.

- The summer windscreen washer fluid Prista is diluted with water in a 1:10 ratio.


The questions below refer to the product’s applications.

Can we use the summer fluid during winter time?

No! It does not possess low temperature properties and hence the risk of freezing.  

Is it wise to use the winter fluid during the summer?

No! The winter fluid contains only a minimum quantity of organic dirt removal additive as there are no insects in winter.

Is it possible to use plain water during the summer and autumn?

Using only plain water in warm weather is a cheap but dangerous solution that poses risks, such as:

- Scale formation;

- Poor washing ability;

- Clogging.

Does the colour of the fluid matter?

The colour does not determine any quality indicators or seasonal use. It is a commercial indicator and a colourant to distinguish the product from water.

What is the product’s concentration?

The products are available as premixed solution, which is more convenient to use in winter, and as concentrated formula. For optimal performance follow the manufacturer’s recommendations indicated on the packaging.


To make driving a pleasure, we advise and recommend that you use windscreen wiper fluids of manufacturers with a reputation for product quality over the years, whose product labels contain the accurate information about ingredients and dilution instructions. Despite the fact that this product needs only topping-up, and the expense may seem needless, maintaining the correct concentration of the aqueous solution and the proper condition of windscreen wiper system - nozzles, sprinklers and wiper blades, will ensure good visibility during travel and is an essential factor for safety on the road.