Permanent air filters any good?

#1

Hi all, as it is time once again to change the air filter on my car, I was thinking about an ad I saw for a permanent air filter that supposedly never needs changing. Has anyone tried these, and a)are they really better than the regular ones changed every 3 months and b) do they really last as long as they claim to?

#2

Is this, by chance a “washable” filter, such as K&N? Do you have to apply some sort of oil to the filter after you wash it? You’re question comes up a lot.

If these filters were “better,” don’t you think they’d be standard equipment? There have been problems with the filter oil migrating to the mass airflow sensor (MAF) and causing failures.

I recommend you continue to use the standard replacement filter, and change it at the interval recommended in your owner’s manual.

Who changes air filters every three months? The air filter replacement interval for both of my cars is 30,000 miles under normal circumstances. If you’re replacing your air filter every three months you’re wasting money.

#3

Unless you are driving across the Sahara there is no need to change the air filter every 3 months. Once a year is usually more than adequate. The re-usable air filters (K&N for example) do flow more air, however they don’t filter quite as well as a standard paper filter. You also must take care when re-oiling them. Many people put too much oil on the filter and sometimes the excess oil alledgedly burns out the MAF sensor.

#4

I don’t use them because they require more work (wash and reoil), they filter no better (maybe not as good), and they potentially may cause problems. The do not improve mileage, but they may offer minor, full throttle only power increase.

#5

What kind of car do you have? I’ve never heard of a filter needing to be changed that often, even under the severe service schedule.

#6

Funny - my OM says to do it every 15K so that’s what I’ve been doing. That’s the brand I couldn’t think of earlier - K&M. I don’t know if they require any maintenance, haven’t looked into it any further yet, but according to what everybody’s saying here, it seems like I should just stick w/the regular ones. I think you’re right - if they were “better” then they’d just be standard and we’d all pay a bit more in the purchase price for them.

#7

Are you sure the owner’s manual doesn’t say “inspect” the filter or “replace if necessary” every 15k? The air filter change interval totally depends on what conditions you’re driving so usually a firm “replace” interval is not specified.

The reason why the carmakers all use paper filters I think has more to do with what happens when they don’t get changed. With a paper filter, if the owner ignores it it’ll just get plugged up and cause running issues but it will continue to filter the air. With an oilable filter, if the owner doesn’t recharge the element, air will still flow through it and the car will keep running fine, but it’ll stop filtering! The car makers want to make their cars as neglect-proof as possible, so the paper filter makes sense.

There’s been some testing out there of the K&N filters and though it seems clear that they don’t filter extremely small particles as well as the paper filters, it’s not really clear if particles that are that small are actually harmful at all. The airflow sensor issues caused by them is usually due to someone improperly over-oiling the element-- properly done they shouldn’t cause problems. However, on an otherwise unmodified car, there’s really no reason to use one. The claims K&N makes about power might be true at wide-open-throttle but the economy claims are very dubious on any modern car.

If the reusability is the main draw, there’s a filter out there which I believe is made by Fram that you can supposedly just wash out with a garden hose. I don’t know much about them, so I’m curious if anyone else has an opinion about them.

#8

They aren’t worth the bother. Who do you know who can’t afford to replace an air filter? If there is any damage to the filter, you’ll have to get a new one. Until then, your engine eats dirt. Nobody changes air filters every three months even with 15,000 miles in that time. If you have a bullet shaped air filter, you have a good one already. If your air filter is huge like a GMC truck with a 4.8 engine, I’ll bet you could go a few years before changing filters. A small air compressor will clean the dirt out of a filter in a hurry too.

#9

Unless you are driving across the Sahara there is no need to change the air filter every 3 months

I don’t live anywhere near the Sahara…and I NEED to change mine ever 3 months…It’s FILTHY after 3 months (10k miles).

#10

A small air compressor will clean the dirt out of a filter in a hurry too.

True, but it will not get the stuff that is really clogging it, only the easy stuff on top. I suggest no bothering to clean any filter, they are just too cheap to play with, replace it.

#11

If you’re going through air filters every 10k miles there is something wrong. What is the make/model of your car? Is the air filter black or greasey when you replace it?

#12

This is in my “pay me now, or pay me later” catagory. You spend money for multiple paper air filters, or you pay for multiple cleaners, or you pay more money for a longer lasting paper filter. either way somebody gets your money.

#13

Nope…nothing wrong…Been that way with my current Toyota and Pathfinders…A lot of construction…and a lot of cars on road which kick up a lot or dirt and dust.

#14

One trouble with filters with oil on modern vehicles is that modern vehicles have an air flow sensor between the filter and the throttle body. If you don’t oil the filter properly after you clean it, you can contaminate the sensor. I would not mess with them.

#15

In my opinion reusable air filter is best investment. In fact all my cars I had, all got K&N. It seems like after 10.000 kms it’s getting a little dirty, but filtrates better. You could get K&N cleaning and lube kit, but I never used a K&N cleaner (cloth washing detergent bath seems working great), but I do oil it with K&N oil. I have my other car going for over 90.000 kms with K&N filter and I have nothing bad to say about it. Except cleaning, that’s pain in the ass part. Gas mileage seems to be better then with reusable filter tho.