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What Oil Filter Do I Need? (+ How To Pick One)

September 14, 2021

“What oil filter do I need?” 

That might be a question running through your mind at an oil change.

What features should you consider in a car oil filter?

Do you really need that high-capture efficiency filter that your mechanic is recommending? 

Don’t worry.

In this article, we’ll go through several oil filter-related topics to clear these questions up and help you pick a suitable filter for your car engine.

This Article Contains

Let’s begin.

What Oil Filter Do I Need?

Your car’s oil filter plays a critical role in removing contaminants from your motor oil. Clean oil in your lubrication system not only helps your engine perform better, but also protects it from engine wear.

Most vehicles will have one oil filter, a primary oil filter. 

Some may have a secondary filter, which works separately. This is more common in a diesel engine as these produce more combustion contaminants that end up in the crankcase.

Your oil filter choice will come in grades from good to best, though any oil filter that fits will work

If so, does it really matter which engine oil filter gets fitted?  

It depends. 

Here are some tips to help you decide:

Tip A: Match Your Driving Style 

A premium oil filter may be a good fit for stop-and-go traffic — to cope with traffic jams that frequently cause more oil pressure variations than driving at a constant speed. The wrong filter might crack its bypass valve too often, pushing unfiltered oil into your engine.

High-performance filters would be for cars driven to the max. And if you’re a racer, it’d make sense to use a race filter that can handle those light engine oils. 

Tip B: A Bigger Filter Isn’t Always Better

Just because a larger filter will fit your engine threads, doesn’t mean it’ll work better. It might have a less suitable filter media, bypass valve, or flow rate. 

Follow manufacturer recommendations for efficient engine oil filtration, as the wrong filter will give you the opposite effect.

Tip C: Use A Good Engine Oil Filter For Synthetic Motor Oil

If you’re on an extended oil change interval or use synthetic oil, then reputable, upper-end filter brands (like a Fram oil filter or those from Motorcraft) are probably a good idea. 

These premium filters will help maintain clean oil during those extended oil change intervals, or keep costly synthetic oil clean longer. The better the quality of an oil filter, the better its filtration efficiency. 

However, if your car engine uses conventional oil and you stick to a regular filter and oil change schedule, the best filters aren’t necessary.

D: Use Synthetic Oil Filters For More Efficient Filtering

You don’t need a synthetic oil filter for synthetic oil — don’t get these mixed up. 

The “synthetic” in synthetic oil filter refers to its filter media. It uses synthetic media instead of traditional pleated paper. 

Synthetic media is generally better at trapping small particles for longer periods. It means more mileage on your engine oil before a change is needed. 

If you’re thinking of using a synthetic oil filter, look for one that provides a 10,000 mile protection with around 98% filtration efficiency. Combine it with synthetic oil (rather than conventional oil), and you’ll have a duo that’ll go quite a distance!

You now know how to select an oil filter that’ll suit your needs. 

Let’s go over some oil filter properties that may also have an impact on your choice.

4 Factors To Consider When Choosing An Engine Oil Filter

Here are 4 basic filter properties that affect how a car oil filter functions, whether for a gasoline or diesel engine:

1. Size And Capture Efficiency

Tiny particles that escape your air filter (like airborne sand and dust) will get into your lubrication system, eventually suspended in the engine oil. 

A typical economy-grade oil filter will have 95% capture efficiency at 40 microns. This means that the oil filter will remove 95% of particles larger than 40 microns on a single pass. The remaining 5% gets through, with little to no performance for under 40 microns.

You’ll find premium oil filters that have filtration efficiency at 95% or better at 10 microns, and these can cost well over $10.

Here’s the interesting thing — about 80% of typical road dust is smaller than 25 microns, so investing in a premium oil filter might not be a bad thing, as smaller particles can generate more engine wear

2. Dirt-Holding Capacity 

If you have a clogged oil filter, the oil filter will trigger its bypass valve so the oil pump can push unfiltered oil through and prevent engine oil starvation. 

The oil filter dirt-holding capacity tells how long it’ll last before going into bypass. This is particularly important if you plan an extended oil drain without a midpoint filter change, or if you drive in very dusty environments.

Diesel engine oil filters are typically larger with a higher holding capacity than gasoline engine oil filters because of their propensity to produce more soot. 

Unfortunately, oil filter brands generally don’t detail dirt-holding capacity, so you’ll have to rely on changing the filter at the recommended intervals.

3. Pressure-Flow Profile 

Your oil pressure gauge will show oil pressure rising as dirt accumulates until the bypass cracking pressure is breached. 

Typical oil filters with an internal bypass valve will crack around 10-12 psid (pressure differential), allowing oil flow to resume.

However, the pressure-flow profile on aftermarket oil filters isn’t commonly available. You don’t need to worry, though, as oil filters are designed to perform within the practical limits of day-to-day service. 

4. Design And Fabrication Integrity

Automotive filters aren’t just about their filtration media. The construction, design, and attention to detail in automotive filters are essential. Remember, oil filters can’t be tested for performance or structural integrity before they’re sold. 

That said, a good oil filter will have a:

Next, let’s see what a high-capture efficiency oil filter does and why it might be good for your engine oil. 

Why A High-Efficiency Oil Filter Might Be A Better Option 

Most engine wear comes from particles between 5-20 microns

The more contaminants your oil filter keeps out of your lubrication system, the better engine performance you’ll get and the longer your engine’s life. The best high-efficiency oil filters can capture around 10 microns of particles, and sometimes, smaller. 

Extensive engine oil testing by the Society of Automotive Engineers (SAE) reports that:

Just keep in mind that the smaller the micron efficiency number, the more expensive it’ll be. The question is whether the costlier filter is worth it if you change your engine oil regularly?

That said, there are some situations where using a high-capture efficiency filter makes plenty of sense. 

Should I Use A High-Capture Efficiency Oil Filter? 

Let’s say a premium oil filter has 98% capture efficiency at 10 microns. 

Here are some situations where you may consider using it:

1. Extended Draining Schedule

If your driving habits or environmental conditions necessitate extended oil drains, a premium oil filter can help extend oil life with better protection from small particle accumulation. Combine this with synthetic oil to get the most out of your oil filter.

2. Extreme Cold Cranks

Cold temperatures thicken oil and place high stress on oil filters. 

A premium oil filter is less likely to collapse during cold starts and may have a more responsive bypass valve to maintain oil flow when you have a clogged oil filter.

3. Towing And High Loads

Towing, high loads, or slow speeds on long hills can thin the engine oil film and increase engine wear rates. 

Thin oil films will make engine parts more susceptible to small, harmful particles. High-capture efficiency filters will help minimize this, and better filter element and anti drain-back valve construction will reduce chances of an oil leak

4. Low-Viscosity Motor Oil

Low viscosity motor oils (like 5W-20) tend toward thinner films at operating temperatures. This increases your engine’s sensitivity to small contaminants. Premium oil filters will help keep out those tiny, damaging particles. 

5. High-Performance Engines

High-end sports cars and luxury vehicles have high expectations for engine reliability and performance. They’re a good candidate for premium oil filters and synthetic oil use.

6. High-Performance Driving

If you’re into motorsports, you may want to use a premium oil filter for engine reliability, power, and endurance with cleaner oil throughout a race. Clean oil reduces engine friction, allowing improved combustion efficiency. 

Wrapping Up

Clean engine oil helps improve engine performance, reliability, and fuel economy. 

Good filtration practices apply to all automotive filters, not only the oil filter; the air filter keeps out contaminants from your engine intake, the fuel filter fuel does the same for your fuel. 

If you don’t feel like grabbing your filter wrench or dealing with the oil pan drain plug for a filter change yourself, why not engage RepairSmith

RepairSmith is a mobile auto repair and maintenance solution, so they’ll be able to handle any fixes right in your driveway. They’re available 7-days a week with a convenient online booking process. 
Contact them about your clogged oil filter or any car concern, and their ASE-certified mechanics will be over to help out!