Renault D4F / D7F

Renault's 1.2-litre four — the D-family, in 8-valve D7F and 16-valve D4F forms, and the entry engine of the Clio, Twingo, Modus and Sandero for two decades.

Simple, belt-driven and port-injected. The D4F 16-valve is worth knowing for one specific weakness: the cylinder head and its valve seats are sensitive to overheating, and a head that has been run hot frequently develops valve-seat and gasket problems that recur after a conventional repair. On a car with a history of cooling trouble, that history is the diagnosis.

Otherwise the profile is that of any small ageing engine — ignition coils, the crankshaft sensor, a worn idle actuator, and vacuum leaks producing lean codes. The timing belt is the item that ends them, and at this age it is almost always unknown. The turbocharged TCe versions of the same block are a different proposition and are covered by their own entry.