You may notice that some oil, transmission, or hydraulic filters are marked with a micron number. A micron is a unit of measurement. For what it’s worth, one micron equals one millionth of one meter. A meter is about three feet, so we’re talking small here. Really small. One of the hairs on your head is about ninety microns wide. So, when it comes to filtration and you see a filter marked “ten micron filtration,” that filter will catch any particle that is larger than ten microns across. That’s one ninth as wide as a hair. Now, you may be thinking that something so small doesn’t make that big a difference in your engine, transmission, or hydraulic system. It makes a huge difference.
Why are there particles in my oil?
As your car or truck’s engine runs, the friction of the moving parts makes tiny metal shavings that get into your oil. If you left these metal shavings in your oil and it kept cycling through your engine, they would build up into sludge deposits on the moving parts. This sludge would cause your engine to run less and less efficiently until it either seized up or overheated. Similar things happen in a transmission or hydraulic system if you don’t filter it. So, you need a filter to catch all the shavings in any of these systems.
So should I just get a filter with the lowest micron number?
No. Since the number of microns marked on your filter tells you how small the pores are in the filter element, the lower the micron number you have, the harder it is for anything to pass through the filter. Smaller pores in your filter are harder for your oil or fluid to pass through. The harder it is for your oil or fluid to pass through, the more strain you place on your oil, hydraulic, or transmission pump. So, installing a filter that lets too few microns pass through could cause your pump to wear out quicker.
What if I get a filter with a micron number that’s too high?
If you get a filter that allows too many microns through, your system will not be filtered enough. This will lead to sludge in your engine, wear on your hydraulic cylinders and valves, or wear on your gearbox. Eventually, the whole system you put the filter on would fail.
So, it’s important to get the filter that the manufacturer recommends for your car, truck, or tractor. You can find this in your vehicle’s owner’s manual.