Oil – l'huile
They had to put some oil on the wheel (huile) to stop it making a screeching noise.
Note: You need to know that huile (oil) is feminine because if there is an adjective after huile (oil), it needs the adjective to accord. For example, 'the black oil' would be l'huile noire instead of just noir (black).
Oil is feminine. Imagine our Labrador climbing out of a barrel of oil.