Erratic viscosity results can be
obtained in some cases with oils containing additives. If the gear oil contains
diluents, some of this fraction might escape before a test is completed,
particularly if the determination is conducted at 210 degree F.
Some additives
which are sensitive to
heat may change under similar
conditions or two agents may
react and thus change the final
viscosity. Also, in case the lubricant contains a polymers, such as “Paratac”,
heat may tend to
reduce its effectiveness and in
turn the
viscosity of the mixture.
