Around a third of UK motorists never check their car’s oil levels, leaving mechanics to do the job come service time. That’s according to new research from oil company Castrol, which says levels should be checked once a month to ensure the engine remains as fuel-efficient as possible.

The survey of 1,000 British drivers found 30 percent of vehicle owners never check the oil at all, letting the mechanics carry out checks as part of the car’s annual service. And 32 percent of respondents said they have never checked the oil level in their car or on any previous vehicle, with 12 percent saying they would not know how to check their car’s oil level.

Just 45 percent of respondents said they usually check the oil themselves, with the remainder instead asking for it to be done by a partner, neighbour, relative or work colleague. Around one in five (19 percent) of those questioned said they would check the car’s oil level themselves, but only if a warning light were to illuminate. But Castrol claims most cars’ oil warning lights only illuminate when the oil reserve is at or below the minimum, at which point engines are already at risk of damage.

Motor Oil Debate

Just 24 percent of respondents said they check their car’s oil level every month – in line with recommendations. But it seems a third (32 percent) of respondents freely admit they have no idea how often checks should take place.

With that in mind, Castrol estimates 21 percent of vehicles on European roads could currently be low on oil. And it thinks eight percent are at “immediate risk of damage” because the oil level is at or below the recommended minimum level.

More on vehicle maintenance:

motorists check compatibility e10 petrol Motorists urged to check their car's compatibility with new E10 petrol
british drivers check once year 14 million British drivers check their car once a year or less

“It’s clear from our survey that there is still some work to do in making car owners aware that their vehicle oil levels should be checked regularly, and to build their confidence in doing so,” said Shailendra Gupte, Castrol’s marketing director for Europe, the Middle East and Africa. “Many of our Castrol branded workshops will offer customers free oil checks to help ensure their car engines are running efficiently and effectively.

“Drivers can also view simple step-by-step instructions on Castrol’s website showing just how quick and easy it is to check and top-up engine oil. By doing this monthly, drivers can dramatically reduce the risk of running low, which can severely impair engine performance and efficiency, and potentially lead to engine damage and failure.”