[MoonDog]

Mr. Fixit.

Thanks for replying.

The overflow tube is after the cap. Connected to the normal overflow outlet on the expansion tank and not part of the pressurised system. Therefore it only works when the pressure is greater than 16lbs, is that correct?

The tiny hole is at the top of the recovery tank.

When the car is cold and I check the coolant level in the expansion tank i usually ensure that is is fully topped up. Maybe I am putting too much in?.. Should I leave the level lower?..