Dayton Daily News

Wheels: Last week you summarized that to select the proper oil for use in most vehicles look for the ILSAC starburst on the front of the container and for the proper (specified) SAE rating (viscosity). Is there more that should be checked?

Halderman: Unfortunately, there are more specifications that are often specified by the vehicle manufacturers. Plus, there are concerns from owners of older vehicles. The newer engine oils are designed for the following:

1. Improved fuel economy — friction reducing additives and lower viscosities

2. Reduced exhaust emissions — as a result of this requirement, some of the additives, such as phosphorus and zinc, usually zinc dialkyl dithophosphates (ZDDP), have been reduced to help prevent damage to the catalytic converter. Even a small amount of oil usage could damage the converter so this is the reason for the reduction of these additives.

Wheels: What does this mean really? Is this something that owners of older vehicles should know?

Halderman: It is important because older vehicles use flat lifters instead of roller lifters and it is the sliding friction between the lifter and the camshaft that needs the higher amount of zinc that was present in older oils, but not today. Therefore, if the oil is changed in an engine older than about 1990, an oil supplement maybe the best solution to guard against possible valve train related wear.

Typical supplements, such as General Motors Corp engine oil supplement (EOS) #1052367 (old number) or #88862586. This additive should be used every time the oil is changed in older engines to help prevent excessive wear to camshafts and valve lifters in antique or older vehicles.

Wheels: What about the use of oil designed for vehicles that have over 75,000 miles?

Halderman: The oil that is packaged and sold for use in high-mileage engines do often contain additional zinc needed for older engines. However, they also do not meet the ILSAC specifications and therefore could result in lower fuel economy.

Most high mileage oils are not available in the viscosity specified by the vehicle manufacturer. If the engine is producing blue exhaust smoke or using more than one quart of oil every 600 miles, then I would recommend using this type of oil. If not, then I suggest that you use only oil that meets all factory specified ratings, including viscosity (SAE), quality (API) and fuel efficiency (ILSAC).

James D. Halderman is an ASE-certified master

technician, a member of the Society of Automotive Engineers and the author of 12 textbooks. E-mail Halderman at jhalderman2@juno.com, or write him in care of: Wheels, Marketing Publications Department, Dayton Daily News, 1611 S. Main St., Dayton OH 45409.