i have santro 2005 model few days back timing belt broke due to which i have to open the head of car and done all the work related to head, after that work i noticed my car started to reduce engine oil. ie reducing 1 liter after 2500KM . before that work my car was decreasing not a single drop of oil. moreover there is no smoke from the car. also no leakage where i park the car . i am jsing liquimoly 20w-50 oil as engine is old. please suggest what could be the problem