A car over 10 years old with low mileage may seem like a safe purchase, but there are components that degrade over time and not just from use. Michelin and Continental recommend that tires be replaced after ten years from the date of manufacture, even if they appear to be in good condition and the tread depth is still above the legal limit of 1.6 millimetres. The age of the tires can be checked through the TIN or DOT code marked on the sidewall, with the last four digits indicating the week and year of manufacture.
The timing belt is another element that degrades over time, regardless of kilometres driven. Bosch Car Service recommends replacement between 60,000 and 100,000 kilometres, or every five years, whichever comes first, noting that the correct interval always depends on the manufacturer and vehicle model.
In mainland Portugal, passenger cars are subject to inspections with increasing frequency. The first inspection takes place four years after the first registration, followed by inspections every two years until the vehicle reaches eight years of age. From that age onwards, the inspection becomes annual, meaning a car over ten years old is typically inspected every year.
The British AA association also warns about problems caused by long periods of immobilisation, such as battery discharge, variations in tire pressure, changes in fluid levels, and surface corrosion on brake discs. Thus, in a vehicle over a decade old, the number of kilometres does not tell the whole story, with the maintenance history, component age, and prolonged periods without use being equally relevant.
