Pressurising Coolant.

[rd070707]

I thought i would just put this question here instead of starting a new thread.

6 months ago i had my timing belt and water pump changed and initially had problems with blowing header tank cap seals and loss of coolant. 2 caps later and lots of flushing and it didnt blow the seal again but ever since i will have a tiny leak out the overflow after a long drive / rag.

There were signs of oil in the header and radiator so i changed the oil cooler and had the radiator cleaned out. But to this day it still does it.

There is no pressure in the radiator pipes, no hissing overflow when i remove the cap and no overheating.

Any ideas? Going to get a sniff test done to be sure