Coolant leak

The other day I arrived home for work to find my engine fan running after I'd turned the car off, as it was late at night and I hadn't been sitting in traffic I suspected all was not as it should be, even though the engine temp and oil gauges were reading normal.
The next day I found that the header had lost about 1 1/2 pints but without any physical signs, I also noted both the oil / coolant looked fine and the oil filler cap was also clean.
The next day I drove the car paying attention to the coolant level etc and all seemed well so today I used it for work a journey of 25 miles.
When I came home after a "spirited drive" again the engine fan kicked in after I stopped the car, this time I found that the header tanked was leaking at it's middle seam.
The tank's condition apart from the leak looks like new, is this a common fault or has the previous owner bought a cheap imported tank?

no,it is common fault, but you are not alone .

where does everybody go for spares ?

Try Rimmer Brothers. I have always found them to be excellent.

John

Hi Steve,
You do not mention what car you have, but at a guess it will be one without a coolant alarm.
So if you going to fit a new expansion tank, you need to look at fitting a coolant level alarm.
Rimmers, or Brown and Gammons.
An absolute must.

I've now ordered a new tank and cap from Rimmers.

I've got a 135 sprint.

I got a F for nothing a few years ago because it had an untraceable overheating problem, turned out to be a split header tank.