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Winter washer fluid is unsuitable in spring and summer

Mar 2022

News & Campaigns

Windshield washer

Drivers must have a clear view in every situation. If dirt or water stains on the windshield hinder visibility, this can impair drivers’ concentration and increase the risk of accidents, warn the safety experts at DEKRA. “As we enter the spring and frost abates, drivers are recommended to switch over to summer windshield washer fluid, since the composition of debris on the windshield in the warmer months changes a great deal,” says Thilo Kunst, a vehicle chemistry expert at DEKRA. The summer mixture reliably combats the types of debris that typically build up in the summer months, which tend to include protein-rich insect residues. The solvents in winter washer fluid, which are designed for frost and deicing, are either relatively or totally unsuitable for this – and they frequently leave behind a dangerous film of lubricant.

“An unsuitable windshield washer fluid or just water in the washer reservoir can represent a true safety risk,” warns Kunst, the DEKRA expert. “Especially in the dark or when the sun is going down, light coming from up ahead and passing through a dirty windshield can cause glare, which impairs the driver’s vision, increasing the risk of accidents.” The DEKRA expert recommends using up all the winter windshield washer fluid in the reservoir before changing to the summer mixture.

Windscreen washer system main inspection

Generally, it is possible to mix summer and winter mixtures with one another. Under some circumstances, however, flocculation may occur – for example, if a finished mixture that is not stable in hard water is put into a reservoir that contains a larger quantity of concentrate diluted with hard tap water. Anyone who wants to be absolutely sure can rely on all-weather products with less antifreeze during the transition from cold to warm weather. These will clean well in the summer while also providing protection against frost. The DEKRA expert advises people to stay away from putting dish soap and other household cleaners in their washing fluid reservoirs. “Unsuitable cleaning or washing fluids can cause paints or plastics to blister, dissolve material, and cause stress cracks in headlamps that are made of polycarbonates.”

To ensure a clear view of what lies ahead, windshield wipers that work well are indispensable. If the wipers smear, wiping them down with a clean cloth and water can help from time to time. However, if the wiper blades have become brittle or cracked in the winter, if they produce smears, or if they only clean part of the driver’s field of vision, they must be replaced. In statutory vehicle inspections in Germany, ineffective wiper blades and defective windshield washing systems are classified as major defects that must be fixed before a new inspection sticker can be issued.

“Fogging” and “magic dust” are names for another effect that can significantly hinder a driver’s vision. If the inside of the windshield is not cleaned regularly, matte films of debris consisting of dirt, cigarette smoke, or vaporized plastic can often form unbeknownst to the driver. These also reduce transparency and can easily cause undesired light dispersion on the windshield.

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