hey guys,

im having an issue with my pug 306!

here's the dealio (i'll keep it brief)

306 s16 2.0 petrol...

-blew the head gasket randomly 2 months ago...
-took it to a garage. got it all fixed. brilliant!
-one week later it starts to heat up. when i turn the car off coolant overflows from the cap itself!
-take it back. they replace the cap and find any small leaks and fix them up
-happens again a few days later
-take it back. the replace the thermostat and it seems okay
-happens again.
-take it back. they take the radiator out, get that looked at, its fine. the replace hoses and seals... all looks good. hold pressures but is still loosing water..

long story short is that the cooling system is holding pressure but loosing 1L of water each trip! it seems like when i turn the car off, the water swells up... and then the water leave decreases, then increases like a wave in my radiator..

what could this be??? thermostat? cap? head gasket? all which they replaced... or water pump???

i just want to be able not to worry every time i drive!!!!!

many thanks in advance
D