Lubrication system consists of oil pump, oil filter, oil filler cap, oil dipstick, and oil pan.  The oil pan at the  engine bottom holds the oil.  The oil pump forces the oil through the filter and internal passages of engine, and then the oil drains back the oil pan through other passages.Oil is used to lubricate the moving parts of a engine.  Oil clean dirt

and impurities from the engine into the filter and prevent them from moving back to the engine.  Oil can also remove part of the heat from the engine.  Therefore, changing engine oil frequently will prelong the engine lifetime.

What You Need to Know About Oil Changes
An oil and filter change involves draining out the old motor oil and replacing it with fresh, new motor oil. The oil filter also gets replaced at the same time.
Should I do this service when it�s recommended?
In general, yes. Changing your vehicle�s oil is one of the most important things you can do to avoid bringing large bags of money to your mechanic later on.

However, there�s a lot of controversy about exactly when engine oil gets old and how often it should be replaced with new oil. Because there are many factors at work � how you drive, the condition and age of the engine, the external environment you drive in, and stop-and-go versus highway driving � it�s an inexact science. Owner�s manual recommendations for oil and filter changes vary from 6,000 to 20,000 kilometers.

We recommend that you change your oil and filter every 5,000 miles. That�s our best estimate. It may be too soon for many people and too late for a few, but for the vast majority, 5,000-mile oil changes will help your engine last to a ripe, old age.

You may want to consider changing your oil more frequently if:
You drive like a knucklehead: jackrabbit starts, heavy acceleration or high-speed driving
You live where the climate is extremely hot or cold
You often drive on dirt roadsOil undergoes thermal breakdown due to high operating temperature. When this occurs, the oil becomes less effective as a lubricant. And without a good lubricant (read: expensive), parts of the engine rub together and wear each other out.

Your engine is old and burns oil
You frequently carry heavy loads (several mothers-in-law or other cargo)
Why do I have to do this?

Oil also contains additives that have the ability to neutralize acids. Over time, these additives get used up and stop being effective. Below is the summary of your penalty for disobeying the oil-change, lubrication and filter in your vehicle: