What Does the Oil Filter Do and When Should You Replace It

Clean oil is critical to the health and longevity of your engine.  Your engine’s oil lubricates the internal engine components, helps cool the engine and prevents wear.  As oil circulates through your engine it picks up contaminants that if not removed can cause engine damage.  This is where your oil filter comes into the picture.  It keeps your engine running smoothly by trapping harmful contaminants before they can cause any problems.

What Does an Oil Filter Do?

The oil filter in your car is very straightforward – it filters your engine’s oil as it pumped and circulated through all of the passages in your engine.

When your engine is running, oil is constantly pumped through a series of passages and components. The oil filter sits in this circulation system and works like a sieve, allowing clean oil to flow through while trapping:

• Metal particles from normal engine wear
• Dirt and dust that enter through the air intake
• Carbon deposits from the combustion process
• Sludge that forms as oil breaks down over time

Without a properly functioning oil filter, these contaminants would continuously circulate through your engine, acting like sandpaper on bearing surfaces and cylinder walls causing severe damage over time.

The Anatomy of an Oil Filter

Understanding the components of an oil filter helps explain why it’s so important:

• Filter Media: This is the actual filtering material, typically made of synthetic fiber or paper, pleated to increase surface area. The efficiency of the filter media can be expressed in the Nominal Micron Rating or the Absolute Micron Rating.
  • Nominal Micron Rating: This rating is based on the filtering efficiency of the oil filter at 50% efficiency.  A typical nominal rating is 10 microns.  This means that a filter is capturing 50% of contaminants 10 micron in size.
  • Absolute Micron Rating: This is how capable an oil filter is at removing 98.7% of a specific particle size.  This is a bit more helpful in determining how large of particles are getting past the filter.  Average absolute micron ratings are 25-30 microns.

• Anti-Drain Back Valve: This prevents oil from draining out of the filter when the engine is off, ensuring immediate oil pressure upon startup. 
• Bypass Valve: If the filter becomes clogged, this valve allows oil to bypass the filter element rather than starving the engine of oil. While this means some unfiltered oil will circulate, it’s better than no oil at all.

Signs Your Oil Filter Needs Replacement

Your vehicle will often let you know when the oil filter is no longer doing its job effectively. Watch for these warning signs:

• Maintenance due light:  This should be one of your first signs that you need to service your oil.  Don’t ignore this warning and go thousands of miles past the recommended oil change interval.
• Visual inspection: If you are noticing contaminants on your dipstick then that is a good indication that is time for a new filter and fresh oils

The rest of these signs are going to be present if the first two are ignored.  The danger here is that the neglected maintenance has gone on so long that vehicle performance has been compromised and that you may be facing more significant repairs in the future.

• Decreased engine performance: If your normally responsive car feels sluggish or less powerful, it could be due to poor oil filtration affecting engine performance.
• Unusual engine noises: Knocking, ticking, or rattling sounds might indicate that dirty oil is no longer providing adequate lubrication.
• Dirty exhaust: Dark, sooty exhaust smoke can indicate oil burning in the combustion chamber, possibly due to contaminants bypassing worn engine seals.
• Warning lights: The check engine light or oil pressure warning light might illuminate if oil pressure is affected by a clogged filter.

When to Replace Your Oil Filter

The general rule of thumb is to replace your oil filter with every oil change. But how often should that be?

For most Asian imports, manufacturers recommend changing the oil and filter every 5,000 to 7,500 miles under normal driving conditions. However, this can vary based on:

• Driving conditions: If you frequently drive in stop-and-go traffic, extreme temperatures, or dusty environments, you may need more frequent changes. These conditions are considered “severe” by most manufacturers and may require changes as frequent as every 3,000 miles.
• Vehicle age and mileage: Older vehicles or those with high mileage often benefit from more frequent oil and filter changes as internal clearances increase with wear.
• Manufacturer recommendations: Always consult your owner’s manual for specific recommendations

Oil & Filter Service in Tucson

The oil filter plays a crucial role in protecting your Asian import’s engine. Regular replacement is a small investment that can prevent costly engine repairs down the road and help maintain your vehicle’s performance and efficiency.

At Micro Import Service, we use only high-quality filters that meet or exceed manufacturer specifications for all Asian imports. Our certified technicians understand the unique requirements of these vehicles and can help you maintain your car to ensure it runs smoothly for years to come.

Remember, regular maintenance is always less expensive than major repairs. Schedule your next oil change today by calling us at (520) 795-8724 or Schedule Online!