Cool, clean and dry—it’s easy!

Dr. Robert M. Gresham, Contributing Editor | TLT Lubrication Fundamentals May 2009

To succeed in this industry, make sure the lubricants in your machines embody those three properties.

 

KEY CONCEPTS
• In our industry we are successful when we keep machines cool, clean and dry.
• Always ask yourself, ‘What have I done with this machine since the last lubricant change?’
• Could your car’s engine survive Shirley Schwartz’s ‘Detroit Test?’

To be successful in our industry all you have to do is keep things cool, clean and dry—it’s easy! What do I mean?

Cool, like Steve Mcqueen:


Clean, like drug free:


Dry, like the arid desert, like no alcohol or like wearing Depends:


In our industry we are successful when we keep the lubricant in our machines cool, clean and dry. When we think about the maintenance of our machinery, we should always have this in the back of our minds. How so, you ask?

Take for example, the family jalopy. I am often asked, “How often should I change the oil?” The quick change companies usually say every 3,000 miles. The newer automobiles have change recommendations between 5,000-7,000 miles or more. Soon we will have effective sensing technology on cars that will tell us. But for now, what’s a body to do?

Think cool, clean and dry. Ask yourself what have I been doing with that car (or any machine) since the last lubricant change? Perhaps, you were hauling a trailer on a long, high-speed trip through the desert in August.

Odds are the oil got pretty hot because of the combination of high ambient temperature and the high load of the trailer’s weight. There could be a lot of oil oxidation or at least additive depletion. If the air filter is in good shape, the oil likely is clean from the outside, but there might be added wear debris as a result of the higher load. The oil is probably quite dry due to the sustained engine heat cooking any water off. I’d change the oil pretty soon after the trip and consider flushing the transmission fluid, as well.

Perhaps you live in Detroit, it’s January and you only drive your car to work, just four miles from your house. These are the conditions that Dr. Shirley Schwartz, long-time STLE member and former senior researcher for General Motors, calls the “Detroit Test.” According to Shirley, this is the most severe engine test they have come up with. Why?



The oil is likely clean, at least from outside dust and dirt. But just as the engine begins to warm up, it is shut off for a number of hours. As it cools, cold, damp air is drawn back into the engine, where water in the air eventually condenses and contaminates the oil. When the engine runs, it doesn’t run long enough or hot enough to cook off the water, and thus it continues to accumulate. Shirley reports that they have seen as much as 8%-10% water in the oil, resulting in corrosion and wear as these levels of water overpower the additives. Under these conditions, changing the oil every 3,000 miles might not be enough.

Suppose most of your driving is at reasonable ambient temperatures and conditions and at constant speeds, 50 or 60 miles per hour, for a few hours at a time. The radiator will easily keep the oil cool, the filters will keep the oil clean, and any traces of water will be cooked out. Odds are you could probably exceed the recommended oil change interval without a problem.

At the risk of having pushed this example too far, I hope you get the idea. Run your machines the way they were designed, where the oil will naturally stay cool, clean and dry. Oil monitoring analysis is a key discipline in determining the health of the lubricant in your machines. Most of the tests run on the oil are oriented toward determining some property related to whether the oil has been kept cool, clean and dry. For example, FTIR provides indications of level of oxidation—was the oil kept cool? Ferrography and particle counts—was the oil kept clean? And Karl-Fischer Analysis and crackle tests—was the oil kept dry? Obviously, there are other tests that are run as well, but, again, I hope you get the idea. Through proper oil monitoring analysis you can determine much about the operating history of the machine and determine when to make the lubricant changes, as well as other maintenance operations. This will, in the end, reduce maintenance costs, increase reliability and minimize pollution load—all of which saves money.

When the machines are operated under conditions where the lubricant is kept cool, clean and dry, the machines will be, as chef Emeril Lagassi puts it, “Happy, Happy, Happy!”


Bob Gresham is STLE’s director of professional development. You can reach him at rgresham@stle.org.