What is a Toyota Emina??? Enima??? Check your water pump for signs of leaks. You must use ONLY genuine Toyota coolant in this car. Cylinder head damage may result over time if you do not! Power wash your engine. Any leaks should be easier to see. Stick your finger into the exhaust pipe when it is cold to see if there is any unusual water deposits inside. You may be burning the coolant. Possible intake manifold or head gasket leak. If you find no external leak, then have your head bolts re-torqued. Make sure that your cooling fan switch is working OK. Good luck!!