Description:
Periodic oil and filter changes keep your engine clean on the inside. Motor oil can become contaminated by dust, metallic shavings, condensation, and even antifreeze. Additives break down over time and can also act as contaminants. The best advice is to follow the guidelines provided in the vehicle owner's manual, but every 3,000 miles or 3 months is a good rule of thumb for oil and filter changes. Many car manufacturers today are recommending extended oil drain intervals for some drivers. However, if you regularly make short trips in your car, drive in stop-and-go traffic, idle for extended periods, drive in dusty or dirty air conditions, tow a trailer or live in a cold-weather region, it's best to stick with a 3,000- mile/3-month regimen.

Purpose:
Engine oil lubricates, cleans, and cools critical parts of the engine. The oil's additives also help to suspend dirt, where it can be drained at the next oil change.

Maintenance Tips/Suggestions:
If you change your own oil, be sure to properly dispose of all waste. A single quart of used engine oil has the capacity to pollute 250,000 gallons of ground water. Never pour used oil down the drain or into the ground. Not only is it illegal, it's also harmful to the environment. Used engine oil is converted for new uses, such as industrial fuel or lubricants. Put used oil into original oil containers or other clean, plastic closed containers, with the contents clearly labeled on the outside and bring the used oil to a facility that accepts used engine oil.

SOURCE: CAR CARE COUNCIL