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What Happens If Your Vehicle’s Air Filter Gets Wet?


If your car’s air filter gets damp, your engine won’t perform as well because water will take up the space meant for air to pass through. But if you run the engine for long enough, the moisture will not harm your car or engine at all.

There you go.

It’s really that simple – if you’re just looking for the answer to this surface level question.

But if you look a look a little further beneath the hood (pun intended) there’s a secret about your air filter that you may not know.

It’s a secret that can very easily cost you over $3,000 or more if you don’t know it.

And I’ll gladly share it with you, because it’s worth knowing. But first, you’ll need some context.

Why Do Air Filters Get Wet?

Your air filter can get wet for a whole heck of a lot of reasons. At the end of the day, your air filter is a vacuum and can suck up everything from rain, snow, mist and condensate in your engine.

When your engine is running it has to suck in a lot of air to keep running. In the process of doing so, a lot of other stuff will end up getting pulled along with the air.

Your air filter’s job is to catch things before it gets into the engine, which sometimes means water gets sucked in as well.

Which raises the question…

Is It Bad To Use A Wet Air Filter?


Yes, I realize this is a little bit different than the first answer I gave you in the beginning.

But let me explain and I think this will make more sense.

Assuming your car is running normally, your air filter probably won’t get wet enough to the point where you’d ever have an issue.

For example, a lot of people are worried about what happens if their air filter is rained on.

And luckily, that’s not something you really need to be worried about.

When your engine is running, it’s pretty damn hot. This heat when combined with the sheer volume of oxygen being sucked into your engine is more than enough to evaporate small amounts of water.

In most cases your air filter isn’t going to be exposed to enough water where it’s going to be an issue. Rain is an example of this. Our cars are designed with the understanding that some rain will get under the hood, in addition to splashing puddles and all that good stuff.

So assuming you’re just doing regular driving, you shouldn’t have to worry about your air filter getting rained on.

But it’s a much different story if you leave your air filter out in the rain for some reason. But why would you do that? You don’t just take your air filter off the car every time you get home, do you?

There’s probably someone out there who does. No judgement. I wear mismatched socks, which some people think is weird.

Be yourself, even if that means taking your air filter off every time you get home. Just make sure you put it somewhere dry!

Because with your air filter, it’s not a matter of wet, but of how wet.

As your air filter gets wetter and wetter, your engine performance will go down, especially at high speeds. You’ll notice that your engine has to work harder to produce the same amount of gas.

And even worse, a soaked air filter can actually do some damage. For example, I’ve seen a few cases where a soaked air filter most likely caused the mass air flow sensor to short circuit.

For my Honda, the MAF sensor costs around $75 for just the part, and will be more when you include your local labor rate.  The total repair cost can set you back over $100.

Obviously you’ll want to avoid that happening if possible. The best way to avoid having a problem with a wet air sensor is to understand the symptoms of such a thing.

Then you can diagnose the problem and fix it before it becomes a problem, as I’m going to show you.

What Are The Symptoms Of A Wet Air Filter?

A wet air filter generally reduces performance. The wetter it is, the more noticeable the loss of performance.

Some major symptoms your air filter is wet are:

  • Engine misfires
  • Rough idling
  • Difficulty starting the engine
  • Engine coughing or vibrating when running
  • Reduced power
  • Gasoline smell

The reason you’ll notice these is because a wet air filter will reduce the amount of air getting to the engine, which causes these symptoms. The symptoms of a wet air filter are very similar to the symptoms of a dirty or clogged air filter.

The funny (or unfunny, depending on how you look at it) is if your air filter gets wet frequently, that can lead to it getting clogged. Whether that’s because of mold or mildew building up, or because water and dirt can combine to form a nice mud coating which will mess your air flow up.

With that being said…

A Wet Air Filter (Probably) Isn’t The Reason Your Car Isn’t Starting

Sometimes my customers ask me if a wet air filter is to blame for their car not starting. In 20 years as a mechanic, I haven’t seen a wet air filter cause a car not to start.

Theoretically it’s possible if your filter is completely waterlogged, but for that to be the case chances are your air intake is also flooded and you have bigger problems.

More often then not, it’s your spark plugs and cylinders that are flooded, not your air filter.

You can check if this is the case by removing your spark plugs and setting them out to dry. Then, crank the engine to get any water out of your cylinders. Replace your spark plugs and check after things are dry.

If your car starts, your air filter wasn’t the problem.

So yes, if water gets into the air filter, your car will probably start unless your air intake is completely waterlogged.

And at that point you have other problems.

Okay, But What About Cleaning? Can You Wash Your Car Filter With Water?

Guess what? There are definitely reusable air filters that you can clean and reuse. Even better you can wash them with water with no ill effects.

Just make sure your car isn’t using a paper air filter, which you really don’t want to clean with water.

 Your air filter is typically located in a plastic or metal box which you’ll need to open up before you’ll be able to get to your air filter. Older cars may require you to unscrew a section of the case while newer cars can usually be unclipped.

If your car’s air filter is very dirty (and I’m talking grimy to the point where you can’t really see the original color) you can clean it with water. Otherwise you’re better off using a vacuum to clean it.

Here’s how you clean your air filter with water. I personally recommend doing this on the weekend because you’ll need to leave the filter out to dry for about 24 hours, so you don’t want to have anything to do. There’s nothing better then doing this on a Sunday morning during football season.

What you’ll need:

  • A clean bucket
  • A clean towel
  • Laundry detergent
  • Some free time

What you’ll need to do:

  1. Start by filling your clean bucket with water. You’ll want enough water in the bucket to submerge the filter completely. Depending on the size of your bucket you’ll need to stand the filter up, so make sure you have enough water to cover it. Combine that water with a small amount of laundry detergent.
  2. Submerge the filter in water and move the filter around to remove the dirt. Agitating the filter in the water is also very effective. If your filter is extremely dirty, you may need to change the water and repeat this process.
  3. Continue repeating the process until you’re able to agitate the filter without changing the color of the water. Once you’re able to get to this point, your filter is clean and ready for drying.
  4. Take the filter and put it on a clean towel and give it plenty of time to dry. It may take 24 hours or longer to completely dry.
  5. Once the filter is completely dry, replace it in it’s mount and pat yourself on the back. Well done.

Generally speaking, you’ll want to stick to your car’s service schedule for your air filter, as every vehicle is going to be different. As a ballpark estimate, you should expect your air filter to need a cleaning every 15,000 miles or so.

A large part of this depends on the conditions you drive in though. If you find yourself driving in the desert, or during the winter where there’s a lot of snow and salt on the road, you may be better off cleaning the air filter more frequently.

Just make sure you replace your air filter every 2-3 years, because your air filter will become brittle over time no matter how much you wash it.

Which raises the question…

Can You Drive Without An Air Filter?

Sure you can. Your car will work just fine without an air filter. Some high-performance sports cars don’t have any air filter at all.

But just because you CAN do something doesn’t mean you should.

You can put water in cereal (and people do it all the time) but that doesn’t mean you should.

Oh, and remember how I said no judgement earlier? If you eat your cereal with water I’m definitely judging you. That’s just wrong.

Your air filter protects your car from debris going into your engine. Everything including bugs, dirt, sand, mold, pollen and much more can end up getting sucked into your engine without an air filter.

That’s not necessarily the end of the world if you just drove down the road without an air filter, but over time it can damage the engine if you’re running it without a filter.

The shit that would normally get caught by your air filter can accumulate in your engine and gum up the cylinders and potentially cause damage.

So you’re probably wondering how the hell do sports cars go without air filters?

The answer is disposable income. Sweet, sweet MOOLAH is what drives sports cars.

I don’t mean literally. If I saw a stack of cash driving a Ferrari I would be confused as well.

What I do mean is that an unfiltered engine isn’t expected to last as long as a filtered engine.

But, if you want your engine to last, or not suck up oil like it’s a Johnny Rocket’s cookies and cream milkshake, you probably want to use an air filter.

On a regular family driver, your car isn’t going to see a noticeable increase in performance by removing the filter.

So just keep the filter on. Don’t be one of those people who drives without it. You’ll save a bunch of money by you know, not having to replace your engine.

But let’s take this a step further…

Is Driving In The Rain With No Air Filter Bad?

The good news is this isn’t really an issue. When it rains, the humidity in the air increases but more water shouldn’t get into your engine.

Considering your air filter isn’t really meant to protect your engine from water anyway, you don’t have anything to worry about.

Again, you probably want to replace your air filter as soon as possible because it’s still there to protect your engine from dust and dirt, even though those aren’t as much of an issue when you’re driving in the rain.

TLDR: Keeping Your Air Filter Clean And Not Wet Is Good For Your Engine And Will Extend It’s Life And It’s Performance

That sweet takeaway I promised you from before should be obvious now. A wet air filter will decrease your car’s performance.

If your filter stays wet it can cause the engine to choke or otherwise run rich. Over time this can cause water to make its way into your engine where it can mix with oil and cause a big mess.

So it’s worth it to pay attention for the symptoms of a wet air filter. It can save you the cost of replacing your engine, which can be over $3,000 dollars.

There you go, I just save you some serious money on replacing the engine. I also saved you a few bucks by teaching you how to clean your air filter yourself.

The good news is that I can save you even more than that.

Getting a vehicle service contract can step in whenever your car has an expensive breakdown.

Imagine your engine decides to crap out after this, whether it’s because of your air filter or not.

Suddenly you’re staring down $3,000 dollars or more to get your car back on the road.

Let’s be honest here: I see people in my shop all of the time who completely lose their shit when they find out that it will cost that much to get their car back on the road.

A vehicle service contract with Protect My Car really means peace of mind. Right now in these difficult economic times, the last thing you need is your car breaking down.

But, if you have a vehicle service contract with Protect My Car you’ll only pay $100 dollars for that $3,000 dollar engine replacement. Imagine that level of protection. But your engine isn’t the only thing that will be covered. Coverage includes:

  • Transmission
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Imagine having that type of peace of mind. The peace of mind that Protect My Car will have your back when the repair bills come piling up.

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Meta: We need water to live. Your car? Not so much. Water in your car’s air filter can reduce performance at worst, and potentially damage your engine at worst. Read on to learn how you can prevent this from happening.  

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Protect My Car is a vehicle service contract provider, also referred to as extended car warranty provider, with multiple coverage plans for new and used vehicles with low to higher mileage to help meet your needs and budget. Protect My Car customers work directly with the company for customer service, claims administration and contract financing. No middleman or the need for third-party approval. All Protect My Car Plans include best-in-class claims and customer support, 24/7 roadside assistance, free oil changes and tire rotations and the exclusive PMC Rewards Plan, providing daily deals, giveaways, coupons, and thousands of ways to save money every day. Protect My Car has a 30-day money-back guarantee.

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