What to Know About an Oil Filter Change

Modern vehicles rely on engine oil to run, and filtering this oil is nearly as important to the health of your vehicle as the oil itself.

The first cars on the road didn’t have oil filters as we know them today, making do instead with simple mesh sieves installed over their oil pump intakes. They were needed because oil gets contaminated by fine pieces of metal produced by the grinding of the valves and pistons and gradually loses its ability to lubricate, but they weren’t particularly effective. Modern filters are made with synthetic fibers that do a much better job of removing contaminants.

Mechanic Alan Gelfand confirms that oil filters trap impurities and debris in your oil, and that “helps to keep your engine in good working order.”  In fact, regularly a regular oil filter change is probably the single most important thing you can do to maintain the health of your vehicle.

What Is a Car Oil Filter?

Oil filters keep engine oil as clean as possible for as long as possible.

Engine oil is designed to lubricate moving engine parts and prevent them from overheating. If thge engine loses lubrication, moving parts can get so hot that they actually fuse together, and the engine can seize. If that happens, you can kiss the engine goodbye.

Small pieces of debris and metal filings gradually decrease oil’s effectiveness as a lubricant and coolant, and this causes many of your vehicle’s moving parts to wear out more quickly. Oil filters delay this degradation by collecting and holding the contaminants while allowing relatively uncontaminated oil to flow through.

When Should I Change the Oil Filter?

“Noticing that your engine is running slowly or becoming noisier are common signs your filter needs replacement,” says Gelfand. These issues “are likely due to oil not being able to flow freely owing to a clog.” He also suggests checking your dashboard for oil pressure warning lights that indicate a reduction in oil circulation due to a clog.

Most vehicle manufacturers and mechanics recommend changing your oil filter every time you do an oil change. As a general rule, you should change your oil every 6,000 miles or every six to eight months. It stands to reason that changing your engine oil goes hand in hand with an oil filter change since there’s not much point in pumping new, clean oil through a dirty, used filter.

Why Do Oil Filters Need to Be Changed?

Oil filters have an important job, but they can’t do it forever. Eventually, the buildup of naturally occurring contaminants from the engine will fill your filter to capacity, preventing it from doing its job. A clogged filter reduces the flow rate of oil, causing a built-in pressure relief valve to open so the oil can bypass the filter entirely. This leads to quicker oil contamination, leaving fast-moving engine parts less lubricated and more prone to overheating.

In short, a dirty filter left unchanged decreases engine life by allowing new, clean engine oil to become dirty and ineffective much sooner. That’s why performing an oil filter change every time you change the engine oil is the best policy.

How to Change the Oil Filter

You can change the oil filter only after all the engine oil has been drained from a vehicle. That’s another reason it makes sense to change your filter every time you change your oil. You may need to to jack up your vehicle to access the drain plug and oil filter. Here’s a quick step-by-step procedure:

1. Start by making sure you have the correct type of replacement filter for your vehicle on hand. Check the owner’s manual or search online to confirm what you need.
2. Place a bucket or pan directly beneath the drain plug, unscrew the drain plug bolt from the oil pan and catch all the used oil in the bucket or pan. Removing the oil fill cap allows air into the crankcase and helps the oil drain more quickly.
3. Replace the drain plug when all the oil has drained.
4. Unscrew the filter or filter casing (depending on your vehicle) from its housing, then replace the dirty filter with the new filter.
5. Lift the hood and fill your vehicle with fresh oil until the oil level is between the high and low indicator marks on the dipstick.

About the Expert

• Alan “Ollie” Gelfand is the owner of German Car Depot, an independent automotive service center located in Hollywood, Florida.