Oil has never really been cheap, but at today’s prices, you sure don’t want to be spending any more for it than you have to.
#1 Keep it in
The first and most obvious thing is to keep it in the hydraulic system. Those couple of slow leaks you’ve been putting off fixing are costing you more per day, week and month.
#2 Keep it cool
There’s a lot of good reasons to maintain appropriate and stable operating temperatures. Oil life extension is not the least of them.
According to Arrhenius’s Law, for every 10 degrees Celsius increase in temperature, the rate of reaction doubles.
The chemical reactions we’re concerned with in so far as hydraulic oil life is concerned are oxidation – due to the presence of air; and hydrolysis – due the presence of water.
So the hotter the oil, the faster the rate of these reactions – and exponentially so.
By way of illustration, if you pour some cooking oil into a glass, it’ll take days, even weeks before it darkens in color – a sign of oxidation.
But tip the same amount of cooking oil into a frying pan – which gives the oil a large contact area with air – then heat the begeezez out of it, and the oil will go black in a very short space of time.
#3 Keep it dry
Water too has a number of negative effects on the oil. In so far as oil life is concerned, it can chemically compromise (hydrolyze) the additive package. For example, the antiwear additive ZDDP is prone to instability in the presence of water.
#4 Keep it clean
Unless you’ve been living in a cave, you know when it comes to hydraulic oil: cleanliness is next to Godliness’.
But particle contamination also affects oil life. Certain wear metals act as catalysts which increase the rate of oxidation and hydrolysis.
Particles can also attach themselves to additives in the oil, resulting in additive depletion when these particles are captured in the system’s filters.
So to wring the most out of every drop of your hydraulic oil, keep it in; keep it cool; keep it dry and keep it clean.
And ONLY change it when base oil degradation or additive depletion demands it be changed.
Till next time.