The Scanning Brookfield Technique: Background and Evaluation of the Low Temperature Performance of Engine Lubricants

Under low temperature conditions, paraffins in a lubricant crystallize and form structures which may impede oil flow. The size of the wax crystals and the strength of the three dimensional network formed depend on parameters such as temperature, cooling rate and soaking time, as well as chemical nature of the wax and other components in the oil.

To evaluate lubricant flow under these conditions, many test methods have been developed, from the simple pour point test (ASTM D 97) to sophisticated tests such as the MRV TP-1 (ASTM D 4864). In the early 1980's the Scanning Brookfield Technique (ASTM D 5133) was developed and has progressively gained acceptance so that it is now part of the ILSAC GF-2 specification. The Scanning Brookfield provides continuous measurement of viscosity at very low shear rate and decreasing temperature.

After presenting background information on the Scanning Brookfield Technique, we examine its use with modern engine lubricants and evaluate the effect of PPD's on the Scanning Brookfield and MRV TP-1 viscometrics of engine lubricants.