ASTM D7110 Standard Test Method for Determining the Viscosity-Temperature Relationship of Used and Soot-Containing Engine Oils at Low Temperatures
13. Procedure for Testing Samples
13.1 Computer Method:
13.1.1 Use manufacturer's cooling program and instructions for its use for testing unknown oils on programmable cooling bath.

13.1.2 Set cooling bath to hold at -5 °C until test is begun.

13.2 Follow equipment manufacturer's instructions for entering identification of samples and sample cells into computer program.

13.3 Follow 12.2 to properly preheat the oils in preparation for analysis. It is critical to the test method that this preheating step be followed precisely as described.

13.4 Zero the viscometer head according to equipment manufacturer's instructions.

13.5 Place test cell from 12.3.1 into test cell adapter according to manufacturer's instructions.

13.6 Fasten test cell and adapter to viscometer head after hooking rotor shaft to viscometer motor shaft.

13.7 Place the assembled test cell and viscometer head onto the programmable liquid bath within 20 min of removing the test oil sample from the preheating oven or water bath.

13.8 Set up the dry gas flow at approximately 10 mL/min. for each test cell.

13.9 Set the viscometer speed first to 12 r/min for 10 min to homogenize the oil and then set the rotor speed to 0.3 r/min.

NOTE 10 - While performing the round robin testing to determine method precision, it was observed that for some highly viscous samples, after the homogenization was started at 12 r/min, the torque on the rotor exceeded its maximum. This caused the rotor to stop in order to prevent damage to the viscometer head. Analysis of the data from the round robin indicated that this phenomenon did not result in statistical outliers in the data set. Therefore, it was concluded that if the homogenization step stops prematurely because of excess torque, the test method is still valid.

13.10 Watch the viscometer torque or viscosity readout and when the viscometer readout is reasonably stable at -5 °C (approximately 15 min), turn on the computer program and simultaneously initiate:
13.10.1 Cooling program on cold-bath, and

13.10.2 Data recording on computer according to bath manufacturers' instructions.

13.10.3 At the conclusion of the test, use the special computer program for data analysis and determination of critical pumpability temperature, Gelation Index, and Gelation Index Temperature according to the manufacturer's directions.

NOTE 11 - It is necessary to complete Section 11 for calibration of viscometer and cells before using the computer program or the program will not be able to accept information generated during the analysis of test oils.