One of the latest in the febi series of ProTips addresses an issue which arises with the coolant expansion tank on certain Ford models. 

The replacement expansion tank is febi 188342, which fits the Ford B-Max 2012 to 17, Ecosport 2012 on, Fiesta IV 2008 to 17, KA 16 on. 

Problem - These models can experience coolant loss and engine misfiring, but only when the engine is at operating temperature and under load. The engine management lamp will also be illuminated.

Cause - Due to thermal stress and engine drive cycles with dramatic changes in temperature, the coolant expansion tank becomes brittle and discolours, leading to cracks appearing in the plastic and sporadically leaking coolant. Under certain conditions this can result in hot coolant being forced under pressure over the engine, soaking the ignition leads and spark plugs with coolant. This leads to the engine misfiring. 

Solution - The technician should check the condition of the coolant expansion tank. If it has discoloured then the plastic has become brittle with age and could be at risk of cracking and leaking. If found in this condition during routine maintenance replacement is advised before any coolant loss issues occurs. 

If the vehicle is displaying symptoms of an engine misfire, the technician should check for any fault codes stored in the engine control unit and then remove the ignition leads, inspect for corrosion and condition and for any coolant build up around the spark plugs, replacing parts as required. 

To fit a new coolant expansion tank it may be necessary, depending on the model, to remove the headlamp for ease of access. To do this, unclip all hoses and pipes, drain the excess coolant, then free the expansion tank from the metal tags securing it to the inner wing. 

The expansion tank should then be replaced with febi Expansion Tank 188342 and Cap 105933. This is clipped into place, with all hoses and pipes refitted. The technician should then top up the cooling system with fresh coolant mixture and refit the headlamp as required. 

To ensure good operation start the engine, check for any leaks. 

For more technical information please visit: www.partsfinder.bilsteingroup.com

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