Choosing Oil for Your Vehicle - dummies

Choosing Oil for Your Vehicle

Choosing the right oil for your vehicle is easy. Just ask yourself the following questions:

  • What kind of oil have you been using? If you have an old vehicle that’s been running on single-weight oil for most of its life, it’s built up quite a bit of sludge because some single-weight oils don’t have detergent in them. If you suddenly switch to a multi-viscosity oil, the detergent in it will free all that gook in your engine, and the gook will start to slosh around and really foul things up. It’s better to let sleeping gook lie unless you want to invest in having your engine cleaned. The engine would have to be taken apart and put back together again, and you could start trouble where none existed before. If your car is running well, don’t switch to another oil. Stick with the same old stuff you’ve been using.
  • How old is the oil in your car? How many miles have you driven it? If your car has been logging a great many miles and has been running on 30- or 40-weight oil, multi-weight oil is not going to be consistently thick enough to lubricate the worn engine parts, which have become smaller while wearing down, leaving wider spaces between them. To keep the oil thick enough to fill these gaps, switch to heavier single-weight oil as your car gets older and starts to run more roughly or to burn up oil more quickly. If you’ve been running on 30-weight oil, switch to 40-weight, at least during the summer, when oil tends to thin out.
  • What kind of oil does your owner’s manual recommend? Is your vehicle still under warranty? Be sure to use whatever weight of oil the owner’s manual recommends; the manufacturer knows what’s best for each vehicle it produces. Using something other than the recommended oil may invalidate the warranty on a new vehicle.
  • Do you live where it’s very cold? Hot? Is it mountainous? Are there sharp changes in temperature where you live or where you’re going? Multi-weight oils cover a range of temperatures. Consult a viscosity chart to be sure that the oil you use will flow properly under extreme conditions.

Whenever you buy oil, look for major brands, such as Pennzoil, Quaker State, and Valvoline, or check Consumer Reports. Good brands of oil are often on sale in supermarkets and at auto supply stores, so if you want to save money and you spot a sale, buy a case and stash it away.

No matter how crazy about recycling you are, never put recycled oil in your precious car. You don’t know where that stuff has been.