mileage

[merlin]

thinking of buying a cooper s with 40000 miles on clock any known problems to look out for with this mileage

[Gismo]

Welcome to the site ;) the mileage depends on the age of the car!
Make sure the TLC is intact and that the service have been done, check to see at what mileage they were done, the less interval the more it's been thrashed, but, the S engine is pretty strong