| As you probably know, the coolant level in the overflow bottle fluxuates; It rises as the engine heats up and should fall as the engine cools down. The coolant level after the engine is cold should be the same as at the beginning of the engine start. If the coolant system has been opened, it may take 2 to 3 heating-cooling cycles to arrive at a stable level, and it may need extra fluid added to the reservior. Howver, if you have to contine to add fluid several times to maintain a level in the bottle, then fluid is being lost somewhere. Check the condition of the hose that goes to the overflow bottle. Lift it and look for splits on its underside. If it leaks air on engine cooling, air is admitted into the system and the engine will not be kept filled - a bad situation. Other places where slow leaks may occur: 1. Leaky rediator -has a slow leak, slow enough that the evaporation rate of the fluid nearl matches the leak rate. sometimes can be detected by small wisps of steam while stopped with engine running. Odor of hot coolant may be present. 2. Leaking water pump. If the leak is small, it may be hard to see. The leaked fluid exits a drain hole in the bottom of the water pump hosuing. 3. Any hose in the system. Look at heater hoses. Lift up when inspecting. 4. Head gasket leak. 5. If the intake manifold has coolant passages, its gaskets may be leaking. 6. Leaky heater core, and this may make an oder in the passenger cabin. If you are having to add fluid on a regular basis, it is leaking out somewhere (unless it is ovefilled in which case, the excess fluid spills out the overflow tube when hot). | 
