This is the most important under-hood check you can do. An engine cannot run without oil even for a minute without serious engine damage or total destruction! To check the oil level, find the engine oil dipstick and remove it. With a paper towel or rag, wipe off the end of the stick and notice the markings on it. You will usually see a mark for Full and another mark for Add. Check your owners manual to be sure. Push the stick back into the tube until it seats then immediately pull it out to see the oil level. You should not add oil unless the level is below the Add mark and NEVER add oil to bring the level above the Full mark. Your main concern with this check is that oil consumption is not rapidly increasing. If it is, take the car to a repair shop as soon as possible and have it checked out. It is acceptable for the oil to be dark as long as you change it at the recommended intervals. However, it should never be foamy and should never have a strong gasoline smell. If either of these conditions exist, have it checked out soon. Change the engine oil and filter regularly (every 3000 miles or 3 months).

Oil weight, or viscosity, refers to how thick or thin the oil Is. The temperature requirements set for oil by the Society of Automotive Engineers (SAE) is 0 degrees F (low) and 210 degrees F (high). Oils meeting the SAE's low temperature requirements have a 'W' after the viscosity rating (example: 10W), and oils that meet the high ratings have no letter (example SAE 30). An oil is rated for viscosity by heating it to a specified temperature, and then allowing it to flow out of a specifically sized hole. Its viscosity rating is determined by the length of time it takes to flow out of the hole. If it flows quickly, it gets a low rating. If it flows slowly, it gets a high rating. Engines need oil that is thin enough for cold starts, and thick enough when the engine is hot. Since oil gets thinner when heated, and thicker when cooled, most of us use what are called multi-grade, or multi-viscosity oils. These oils meet SAE specifications for the low temperature requirements of a light oil and the high temperature requirements of a heavy oil. You will hear them referred to as multi-viscosity, all-season and all-weather oils. When choosing oil, always follow the manufacturer's recommendation.

Take the simplest of tasks, the oil and filter change. Many car makers recommend one at regular 7,500-mile intervals. But most mechanics will tell you to do it every 3,000 miles. Some independent experts advise 5,000 miles or twice a year. Not even the American Automobile Association speaks with one voice on the question. Its engineers recommend 3,000 miles, while a recent article in the AAA's Car & Travel magazine criticized mechanics who do more than the manufacturer suggests.

Check your owners manual and follow the manufacturers recommendations.