It probably has already been answered on here but I cann't find it. So here goes, I have a 02 2.6 that seems to lose coolant from the coolant tank so you can see the top of the thing inside the tank, after standing for nearly a week enough to put on the coolant low warning. After putting the ignition on without starting the car, pressing the brake to remove the check message, it is replaced by the coolant warning one. I have looked for physical signs both inside the car up under the dash, in the footwells near the HBV as best I can using my hand to check for leaks. Smelt the coolant in the coolant tank for petrol smell nothing, just had a oil change and no water contaminants in it. No oil contaminants in the coolant. The car doesn't overheat and stays at normal temperature, also heater works on hot and cold no problem. I have looked underneath the coolant tank incase it is leaking from underneath, but nothing can be seen. No white or steam coming from the exhaust when the engine is running.
I know when the car is turned off there is no vacuum, so would the HBV be allowed to leak, because of no Vacuum going to it(if that makes sense)? There is no sign of escaping water from it, when the car is running.
Thanks for any replies. I do have a HBV to replace it, I just thought I would ask more knowledgeable people.