The Institute of Advanced Motorists (IAM) has said that leaves could cause glitches in the electronics of modern cars, and has urged drivers to check their vehicles regularly to avoid breakdowns.
IAM said that leaves often get collected in the plenum chambers, the tray-like area under the bonnet, below the windscreen. The charity said that the accumulation could cause problems with engines and braking systems, as well as causing windows to mist up.
Peter Rodger, chief examiner of IAM, said: "Leaves can block up the drains and cause them to fill with water when it rains which then leaks into areas that should be protected from the elements, such as the computers that control the engine, braking systems and other expensive electronic equipment."
He added that trapped water could also make the windows constantly mist up, impairing visibility.
IAM's chief examiner advised drivers to have a look at the plenum chambers and clear out the leaves and any accumulated grime.
Mr Rodger also encouraged motorists to get their car batteries checked: "Autumn can also take its toll on car batteries, as the first frost settles, but some basic maintenance can help to prolong battery life."
© Press Association 2009