Some Answers That May Surprise You

1. False. Adding a can of additives to your oil will not increase its useful life. In fact, extra additives can even harm your engine by disturbing the chemical balance of the oil. A quality oil (like Pennzoil) already contains all of the additives your engine needs. That's why many owner's manuals discourage the use of oil additives. Some people think they can add a can of additives instead of changing the oil. Not true. Additives can't clean dirty oil or compensate for other problems such as dilution and oxidation.

2. True. Using the wrong oil can void your engine warranty. Check your owner's manual for the correct API category and SAE grade.

3. False. Dirty oil is not a sign of engine problems. In fact, it's a good sign. It means your oil is doing its job: picking up engine contaminants and keeping them suspended so they can't collect on engine parts. When you change that dirty oil (and your oil filter), you remove the contaminants.

4. True. Some motor oils improve your gas mileage. These oils contain friction modifiers and provide optimized lubricating properties that permit engine parts to move more easily, reducing power requirements and giving you more miles per gallon. Oil labeled "Energy Conserving" can increase fuel economy by l.5%. Oil labeled "Energy Conserving II" can improve fuel economy by 2.7% or more. These increases are compared to a standard test reference oil.

5. True. SAE l0W-30 motor oil can be used for year-round driving in areas where temperatures never drop below zero. Multigrade oils like SAE l0W-30 protect your engine in both cold and hot weather. Pennzoil markets a variety of multigrade oils for different climates and driving conditions.

6. Severe service includes short-trip driving in dusty conditions, cold-weather driving, hot-weather driving, driving in mountainous terrain, and towing trailers, boats and other items.

   Most motorists are surprised to learn that one example of severe-service driving is the legendary little old lady who only drives her car a few miles to church on Sunday. But it's true. She should change her oil more often than the long-trip, highway-speed driver. The problem with short-trip driving, driving in heavy traffic (stop-and-go driving), and cold-weather driving is that the engine never warms up enough to boil away the water or fuel contaminants that form in the oil during operation.

   Driving in dusty conditions also causes problems, since no air cleaner is l00% effective. Dust grinds away at metal parts in your engine and combines with oil to create sludge. The same thing happens if you drive on roads that have been salted or sanded for icy conditions.

   Hot-weather driving is considered severe service, because it can cause oil to oxidize, thickening it so it cannot flow through the engine efficiently. Towing trailers, boats and other heavy items also encourages oil oxidation, as does driving in mountainous terrain.

7. The "W" in SAE l0W-30 stands for "winter." Motor oils that are designed for cold-weather driving are labeled with a number: 0, 5, l0, l5, 20 or 25.

8. You should change your oil filter at every oil change. The oil filter is a strainer that filters out the solid particles of dirt and metal that are picked up by the circulating motor oil. When the filter becomes clogged, a bypass valve allows these contaminants to continue circulating with the oil in the engine, damaging engine parts and creating sludge.

How did you do? Don't feel bad if you didn't choose all the right answers -- most people don't. However, as you can see, knowing more about motor oil can prolong the life of your engine and help reduce your maintenance and repair bills.