Engine oil is one of most important thing for a car because it lubricates whole engine to reduce friction between moving metal parts of engine and it helps to cool down metal parts to avoid expansion of engine parts due to intense heat. If you drive car with insufficient amount of engine oil, after some time engine will heated to a very high temperature and after that lot of problems may possible. Some of them are quick wastage of metal parts, cracking of cylinder head, braking of gasket, braking of pistons etc. Over heating of an engine may lead to sever engine damage. Repairing of an engine is one of most costly repairs of cars.