Question 1

1.6 EcoBoost timing chain tensioner rattle

Accepted Answer

The Focus ST 250's 2.0 EcoBoost and the smaller 1.6 EcoBoost in other Mk3 Focus models can develop a worn timing chain tensioner, causing a rattle on cold start that clears once oil pressure builds. Typical fix: Timing chain, tensioner and guide replacement, best done as a full kit rather than tensioner alone.

Question 2

1.0 EcoBoost cracked cylinder head / head gasket failure

Accepted Answer

Same 1.0 EcoBoost engine as used in the Fiesta of this era: a cracked cylinder head or head gasket failure linked to the coolant system, particularly the plastic coolant elbow near the thermostat housing. Typical fix: Cylinder head replacement and repair of the underlying coolant leak.

Common Ford Focus Problems

1.6 EcoBoost timing chain tensioner rattle

1.0 EcoBoost cracked cylinder head / head gasket failure