This year’s harsh winter has seen motorists go through millions of litres of coolant – to keep their engines running smoothly, and screenwash – to maintain good visibility.

But according to new research from Kwik Fit, over 20% of motorists (six million) have confused the two liquids – with potentially disastrous effects to their car’s engine and bodywork.

As screenwash has a higher freezing point than coolant, adding it to the engine by mistake can easily cause serious internal damage, particularly in sub-zero conditions. The chemical mix in coolant when used in the screenwash reservoir can harm a car’s paintwork, as well as having environmental implications.

Despite these possible coolant calamities, the majority (60%) of motorists are unaware that mixing up the two liquids could be harmful to their car. This confusion can stem from the fact that both liquids contain ‘antifreeze’ chemicals, although in very different levels of concentration.

And a further 10% of motorists (three million) claimed to know the difference, but admitted to ignoring their coolant mixing instructions and adding it in undiluted form to their car’s engine, risking internal corrosion and a failed water pump.

When it comes to coolant colour, almost two thirds (64%) are unaware that coolant comes in a variety of colours, each representing a different specification. The potential for confusion doesn’t end there as not all manufacturers are consistent with their colouring.

Ian Fraser, chief executive at Kwik Fit, said: “It’s easy to mix these two fluids up, particularly as they often look similar in consistency and colour. Similarly, motorists can quickly come to grief by adding the wrong type of coolant or failing to dilute it. What’s worrying is the lack of awareness amongst motorists of how doing so can inflict serious damage to their cars, particularly during these conditions when coolant and screenwash are in high demand.”