Ford Focus RS Head Gasket

The Mk3 Focus RS uses a 2.3 litre EcoBoost four-cylinder producing around 350PS. A significant number of early cars developed head gasket failure, where coolant leaks into one or more cylinders. Ford later revised the engine block and gasket design for production cars.

The signs build gradually: the coolant level drops with no puddle under the car, there is white smoke with a sweet smell on a cold start, and eventually a misfire, often on cylinder four, as coolant sits in the cylinder overnight. Many owners first notice the low coolant warning and top it up without realising what it means.

Ignoring it risks more than the gasket. Coolant in a cylinder can hydraulic-lock the engine on start-up, and repeated overheating warps the head. We confirm the diagnosis with a cooling system pressure test, a combustion gas (block) test and a check of the spark plugs and cylinders with a borescope before recommending anything.

Depending on the findings and the car's history, the repair can be a head gasket with the head checked and skimmed, or replacement with the revised short engine. We explain the difference honestly, including what happens to your car's value and future reliability with each option.