Search Results

The results of analyses on 300 samples of engine oil purchased in the retail market and analyzed in 1991 are discussed. All samples were labeled with the API SF or SG Service category, either alone, or in combination with, an API C category designation. Also, 9 oils previously found to be questionably labeled, from the 1990 set, were repurchased and analyzed. These results are included.

The results of analyses on 300 samples of engine oil purchased in the retail market in 1990 are discussed. All samples were labeled with the API SF or SG Service Category, separately, or in combination with an API C category designation. Also, 17 oils previously found to be questionably labeled, from the 1989 set, were repurchased and analyzed. These results are included.

A Coordinating Research Council (CRC) cooperative program utilizing seven North American diesel-powered vehicles (four passenger cars and three heavy-duty trucks) and eight fuels (three base fuels and five flow improver additive-treated versions of the base fuels) was run in Kapuskasing, Ontario, Canada, between January and April 1981. Minimum operating temperatures for each vehicle-fuel combination were determined and compared with predictions from laboratory tests. Significant differences among vehicles were found and related to fuel system design. The use of flow improvers permitted some vehicles with some fuels to operate substantially below the fuel cloud point. None of the laboratory tests predicted the performance of all fuels in all vehicles, but the LTFT (Low-Temperature Flow Test) and the WPI (Wax Precipitation Index), an empirical relationship combining cloud point and pour point, offered promise.

Four multigrade engine oils, containing the same base oil plus SE additive package but VI improvers of differing shear stability, were evaluated in 80 000 km of high-speed, high-temperature vehicle service. Bearing, piston ring and valve guide wear, as well as oil consumption, oil filter plugging and engine cleanliness were all worse for the engines operated on the low-shear stability oils. The wear differences were traced to differences in high-shear-rate viscosity, while the cleanliness, filter plugging and oil consumption differences occurred because of excessive wear or polymer shear degradation. These results suggest that engine oil viscosity should be specified under high-shear-rate conditions.