Re: What methods are there to test motor oil breakdown in a chemistry lab?

Jonathan,
You have already named the most common tests for testing lube oil.  The 
simplest and most efficient way to see if a lube oil is breaking down is 
by change in viscocity from the origional oils viscocity.  Keep in mind 
that you need to know the viscosity of the origional oil, as they vary 
from batch to batch.

In our lab we also employ two other simple tests to screen lube oil, one 
can be doen by you and the other requires an instrument that you may or 
may not have in your chemistry lab.  The first tests is a tests for water 
and antifreeze.  This test is a hot plate, heated to about 300 degrees F 
with an aluminum pan place on it.  Put a drop or two of the oil onto the 
pan and watch for crackling and bubbling of the oil.  If it does pos and 
sizzle there is water and/or antifreeze in the oil.  The other method we 
use is to look at the oil using infrared (IR) spectroscopy.  As a lube oil 
breakdown, it is actually oxidizing.  When oil breaks down, you begin to 
see a peak at about 1750 cm-1 and it will grow as the oil gets older.

With as much as I hate to say this, determining break down of oil without 
the proper equipment is almost impossible.  Viscosity would be your best 
bet, but even with it, the instruments are costly and require a great deal 
of maintenance.

If you would like to know more about this, you can e-mail me at 
J.Carlin.Gregory@Williams.com

Sorry, I couldn;t have been more helpful.

Carlin Gregory
Staff Chemist,
Williams-SouthCentral