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Can You Use WD40 As Air Filter Oil?

Can You Use WD40 As Air Filter Oil

You already know the importance of keeping your air filter oiled. Equally important is the type of oil you use to keep it lubricated.

Good air filter oil traps dirt, dust and repels moisture.

This type of air filter requires re-oiling to ensure an even sticky coat to work properly – WD40 isn’t a good air filter oil substitute.

For one thing, WD-40 dries too quickly to provide that sticky coat leaving behind residue that can block fresh air from coming into the engine through the intake.

We’re going to look at what makes this type of air filter different from others. And consider some appropriate air filter oil substitutes.

What is an Air Filter?

Regardless of the application an air filter is designed to do one thing: prevent pollutants from entering an ecosystem.

When it comes to the engine in automobiles that ecosystem is the combustion chamber.

Most air filters are in an air box that comes with most cars from factory. Aftermarket air filters can replace the filter that came stock with your vehicle.

More often they’re cone shaped and come at the end of an aftermarket air intake system. The medium used for filtering can be either paper, foam or fabric.

Warning: here comes an over generalization. The combustion chamber is where fuel and oxygen mix to cause combustion.

An air filter prevents bugs, debris, and particles from entering the engine where this combustion occurs. It gives the engine the cleanest amount of air to function at its optimum best.

Doing a few small regular maintenance tasks like keeping an air filter oiled is paramount to avoiding major costs down the road. But not all air filters need to be oiled.

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Types of Air Filters

There are two types of air filters: dry and oiled.

All air intake filters – regardless of the filtration medium used – must meet minimum filtration requirements. That means it must trap a certain amount of contaminants to protect the engine.

Dry air filters are the most common. We’ve all seen them. You likely have a dry air filter under the hood of your car right now. Oil air filters aren’t as common – you usually purchase it as an aftermarket product.

The advantage of a dry air filter is that it require less maintenance than oil air filters. The downside is that they’re more restrictive than oil air filters.

Dry air filters can catch up to 99% of pollutants, while oil air filters catch 98%.

Oiled air filters depend on the thickness of the oil to catch pollutants.

What’s WD40?

WD-40 isn’t just a lubricant.

It’s touted as a multi-use product with a unique and special blend of lubricants that also contains anti-corrosive agents along with ingredients for water displacement, penetration and soil removal.

It’s best used for lubricating moving parts like hinges, chains, wheels, rollers and gears.

I’ve used WD-40 to great affect for loosening stubborn bolts. What I do is spray a thick layer of the stuff on the seized bolt (in a well-ventilated area of course).

Then I give it time to soak into the affected item (usually about 10 minutes). After that, I have at it with a wrench.

WD-40 also protects against rust and corrosion.

The Importance of Air Filter Oil

The right oil acts as part of the filtering system of an oil air filter.

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The filtering media relies on the tackiness of the oil to filter out dust, debris, sand and other pollutants from entering the engine.

If you get an oil air filter as part of an aftermarket intake system, the filter comes pre-oiled with just the right amount of oil to protect your engine.

As we mentioned before, even drop in air filters can be oil air filters. The right air filter oil will help an oil filter last longer than a dry air filter.

Why Isn’t WD40 a Good Air Filter Oil Substitute?

While WD-40 is a great product that’s been around for over sixty years, the lack of focus in its all-purpose design makes it unsuitable for lubricating an air filter.

It’s the reason why people that have tried it for oiling their air filter report that it doesn’t stick, but rather runs off the air filter.

Not only does WD-40 dry too quickly eliminating the tackiness required for proper oil filter lubrication. But it leaves behind a film that restricts fresh air from coming into the engine.

Good Air Filter Oil

K&N air filter oil is one of the best on the market when it comes to air filter oil.

It’s designed as a tacking agent to grab fine particles and hold onto them until the next time you clean your filter.

How many miles can you go between cleanings?

A typical drop in dry air filter can last 15,000 to 30,000 miles. But a properly maintained oil air filter can last up to 50,000 miles before you’ll need to clean and reapply oil.

The cone-shaped oil air filters that come with aftermarket air intake systems can last 100,000 miles before it will need to be cleaned and re-oiled.

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Good Air Filter Oil Substitutes

Good air filter oil will help an oil air filter capture fine particulates like dust, dirt and sand. It’ll also keep water and moisture from passing the filter into the intake.

And good air filter oil prevents the oil air filter from clogging.

Motor oil is a surprising substitute for air filter oil. 90W motor oil or higher has similar thickness characteristics as air filter oil.

Cooking oil can also work in a pinch. Soybean oil tends to have the thickest viscosity.

Automatic Transmission Fluid is sticky and thick enough to aid in filtration.

Dangers of Not Properly Oiling an Air Filter

As mentioned, oil air filters are usually aftermarket air filters with larger pores than stock air filters to allow more fresh air into the engine – even the drop in ones.

If these filters are not properly oiled those larger holes allow pollutants into your engine which can result in issues like burnt valves.

The tackiness of the oil acts as a second line of defense to protect your engine.

How Often Should You Oil an Air Filter?

Earlier we said that you can get away with oiling your air filter every 50,000 miles.

But this is under normal driving conditions.

If you tend to drive your vehicle hard or a lot, I recommend cleaning and reoiling an oil air filter once every 12,000 miles to ensure longevity.