Your Screenwash Questions Answered

It comes as a huge surprise to many people that having an empty windscreen washer fluid tank can actually fail an MOT test. After all, a covered windscreen – especially when driving at speed – is one of the most dangerous things to happen on the road. Considering the surprise about screenwash being on MOT tests, we thought we’d answer some more questions around screenwash.

What is the purpose of screen wash?

As it says on the tin, screen wash is the fluid that’s sprayed onto the windscreen and back window of cars in order to help the wipers clear any obstructions. It might seem minor, but something as simple as a bird doing its business on your windscreen or a thoughtless driver throwing something out of their window can completely reduce visibility – also making it harder to stop in a safe place.

Is antifreeze a screenwash?

While screenwash tends to include some additives to stop it freezing, it’s completely different from antifreeze. Antifreeze, otherwise known as glycol, is used to help cool engines, and is usually made from ethylene or propylene mixtures.

Screenwash often contains ethanol or methanol in order to help stop freezing, but more importantly, to help dissolve any grease on the windscreen. These are usually called “non-residual de-greasers”, and come in handy in a number of mechanical applications too!

Imagine having spilled some milkshake on a mirror; if you just spray water on it and try to wipe it off, you’re likely to just smear it around rather than get it off. Screenwash acts as the detergent that lets you wipe it off.

Can you use water as screenwash?

No, using water alone may help get some forms of debris off your windscreen, but you need actual screenwash to effectively remove grime. Water on its own is not sufficient to clean the screen, because it doesn’t get rid of any oils or grease.

Should you dilute screenwash?

Some screenwashes come as concentrated solutions, so you should only ever dilute these to the right ratios specified by each manufacturer. Many windscreen washer fluid bottles you’d find in petrol stations will already be at the right dilution levels – so you can just pour them straight into the tank.

Where do you put screenwash?

The screenwash reservoir cap is usually in the engine bay and usually has a brightly coloured cap so that it’s easier to spot in low visibility conditions. It will almost always have a symbol embossed on it that looks like some water being sprayed onto a windscreen.

Can you mix windscreen washer fluid?

It’s not usually a problem to mix windscreen washer fluid with different brands. The only problem you might find is that it becomes overall less effective if one brand has a particular additive for a particular application or benefit.

Any other questions?

Hopefully we’ve answered all of your questions! If you have any other questions on your screenwash, windscreen wipers, or windscreen then get in touch with your local Kwik Fit centre.