Journal-News

Halderman: This week is the first of a series on engine oil. By far, I get more letters from readers about engine oil than any other topic.

There are three basic facts that every vehicle owner needs to know about oil. These include:

Fact 1 — The recommended oil change interval, usually expressed in mileage and time, is the maximum interval. It is okay to change the oil more frequently, but not longer than specified. Most vehicle manufacturers recommend that the oil be changed at least every six months and mileage varying from 3,500 miles to 7,500 miles. Some European brand vehicles, using specific high-quality oil, have oil change intervals extended to every year or up to 18,000 miles.

Fact 2 — The recommended oil thickness is called the viscosity. The Society of Automotive Engineers (SAE) developed a viscosity rating system that shows the thickness when both cold and hot. Always use the specified viscosity. Examples of the viscosity include SAE 5W-20 and SAE 5W-30.

Fact 3 — The recommended quality specification can be any or several of the following:

• American Petroleum Institute (API) standard. (The current API rating is SM.)

• The International Lubricant Standardization and Approval Committee (ILSAC) standard. (The current ILSAC rating is GF-4.)

• The vehicle specific standard (These ratings vary by vehicle manufacturer and type of engine.)

Wheels: How in the world could a vehicle owner know all of these specifications?

Halderman: Good question. For those who do not want to know the details, simply ask the technician to use oil that meets the requirement for your vehicle as published in the owner's manual. Look in the index for "specifications" and show this to the service adviser or technician.

Wheels: Do all shops and dealers have all oils?

Halderman: No. This is why it is important to ask whether they use the specified oil. Some oils are very expensive, so it is also important to ask about the cost.

James D. Halderman is an ASE-certified master technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. Submit your automotive care questions to Halderman via e-mail at jhalderman2@juno.com, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.