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I have been reading in a few places that air filters get better with age, is this true? And how much better?

Would it have any effect on quality of the oil or make oil dirty faster?

Or is there not a great deal of difference between new and used filters?

Thank you for your time.

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Where have you been reading this, exactly? I think you might have misinterpreted it. – I have no idea what I'm doing Mar 1 at 10:31
up vote 7 down vote accepted

I don't have any empirical evidence for this, but would say no for two reasons:

  • An air filter will collect more dust, dirt, and debris until it gets so full that it starts pushing the older dust, dirt, and debris through the filter, which is what you are trying to prevent in the first place.
  • As the air filter collects more dust, dirt, and debris, the filter element becomes more restricted causing less air to flow into the engine, hurting performance and fuel mileage.

A dirty filter will not make oil dirtier faster, but as it gets so full and the dust, dirt, and debris (hereafter called "stuff") starts pushing its way into the intake tract, it will cause buildup inside the engine. The "stuff" will get into the engine combustion chamber and create excess wear on all the moving parts. There is basically no way for the "stuff" to get into the oil. Oil gets dirty usually from cleaning excess hydrocarbons off of working parts and from the oil itself breaking down due to heat and age.

As far as the difference between new and old filter, a new filter will clean the air: an old filter won't do such a good job.

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A good answer I would also say the same. I would like to think that manufacturers make the filter to perform at its best from new and that anything after that would be worse. How often do you personally change your filters? I know everyone has their own opinions on when it should be done but I like to get a wide range of opinions before I make mine. – ceefax12 Feb 27 at 23:16

It all depends on what you mean by getting better.

It is possible that, as the very small holes in the filter that let air through start to trap particles, the places where air can get through will get smaller and smaller. Therefore the filter will start to trap smaller and smaller particles. The air filter may get more efficient at filtering, but it will also start letting less and less air through for the engine to breath.

Some fine particles that get into the engine may possible get passed the piston rings into the oil and make the oil dirty, but the majority of dirt in the oil will be combustion soot that gets past the piston rings.

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Another good answer, it's only logical to think that it would get better as it gets blocked but with a trade-off that the engine will struggle for breath. And I was also thinking that any dirt that does get burnt will stick to the bores of the engine and get wiped away by the piston rings which have contact with oil will make it dirty. How often do you change your filter? I know everyone has opinions but I’d like to hear yours – ceefax12 Feb 27 at 23:17
@ceefax12 I don't generally have a schedule, I just check it now an then. I generally change the oil at the same time each year, but I won't have done the miles which would require a service. – HandyHowie Feb 28 at 13:25
ahhh right I see, I was going to go with a 15k miles change because I do a lot of miles, I would easily rack that up within a year. Do you think this is too soon? – ceefax12 Feb 28 at 14:08

The function any filter is to remove small particals. In an air filter,the air is purified form dust particals before entering in to carburattor for mixing of fuel with air. So if tha filter is already full of dust its efficiency to clean the air us reduced and also there would be a blockage in tha air passage . Hence aged filter does not leads any betterment to the vehicle.

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If you are discussing paper or cardboard air filters for the engine they degrade overtime and have to be changed. Oil filters are suggested to be changed with every oil change. There are generally two types of air filters a Cabin air filter and a engine air filter.

It is better in the long run to get a reusable air filter that can be washed and re-oiled to trap dirt and dust better.

Older vehicles like ones with carburetors that had air-filters that were round or oval shaped would get poor fuel economy due to dirty air filters.

Today dirty air filters do not really disturb fuel economy because of computer components. However, engine performance is changed with a dirty air filter regardless of the autos age.

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