Expansion tank

[Btabs]

Hi my expansion tank has a slight leak around the cap I have replaced the cap and there is still a tiny bit of fluid coming through can this be fixed with out getting a new tank and is it ok to drive for now?

 

[scotman]

Get the tank and cap replaced as soon as possible!
These plastic expansion tanks are an engine blowing time bomb. Our engines run very hot. The expansion tanks get very hot and then cool to ambient temperature . They are a highly stressed component. I have seen them fail within 50 thousand miles. Generally, they can be trusted to last for about five years. I make a easily visible full mark with a felt tip pen and monitor the "cold" full level. These components will often times begin "weeping"coolant before they fail.
At motorway speeds the engine will overheat and expire within a few kilometers when the tank decides to give up! I replaced the 2nd tank on my 2011 1.6 SE hatchback this past June, i was at a fuel station and opened the hood to connect some jumper cables to an elderly womans car who had a dead battery. When i revved my engine, a tiny orange fountain of coolant appeared on top of the expansion tank! It had begun to fail at one of the circular indents that are made when it's released from the mold cavity. This part was 3 years old!

 

[LionsTooth]

See https://www.fiestastforum.com/threa...our-fiesta-st-today.1441/page-577#post-452763. The tank is here.