I have 98 XK8, several months ago i developed a leak on one of the hoses to the Heater. So i replaced the hose and the thermostat housing. But poor manuafcturing on the thermostat housing, leaking on the top, i replaced it back to the OEM. Everything looks good no leaks. Now everytime the vehicle cools off, i have calapse hoses, low level coolant warning. Again no leaks that i can detect, but the antifreeze is being dumped into the atmospheric bottle under the right fender. Help anyone!!!!! a dealer mention to me to change the thermostat, i did. I even changed the antifreexe reservour and cap. No luck.. I also replaced all of the clamps, just incase one of them was bad. Any ideas.

 

The simple answer is to 'rent' a set of coolant system pressure testing equipment from a local auto parts store. Pump up the system cold and the leak should be evident.