I’m with Keith. I just replace at 20,000 for $20 along with the cabin filter. If its wasted money, it wouldn’t be the first time I wasted $20.
“There really is no good ‘home’ method for testing air flow”
A gauge like this will indicate actual restriction without opening the housing.
Engine air filters should be replaced. I would follow the schedule from the manufacturer because they know more about the engine than anyone posting here does. But, yes, a good rule of thumb was mentioned here— it should be pretty transparent when put up to bright sunlight. Remember that the air downstream of the filter still went through the filter, and if it’s dirty it will strain under a load, and if there isn’t enough air it will reduce MPG.
or a rodent may have chewed it apart
A couple of years ago, my check engine light came on, with a P0100 code. Rodents had crawled up into the air intake snorkel and chewed the air filter, making a big bed of paper. Much of that paper had been sucked into an intake screen - causing it to plug and restrict airflow to the engine.
I cleaned it up and installed a new air filter. A week later the light came on. They chewed up the filter again!
Placing Dcon in the air filter box for a couple of days did the trick.
Wow, what a wonderful bunch of answers. What I did not tell was that I did change the air filter eventually; around 50,000 miles, and I think I did get slightly better mpg, on my 200 mile run to my daughters. Maybe 22 instead of 21 on my 2006 Toyota Tacoma. Was this psychological – maybe I had a good tail wind? Cars are strange, they always seem to run better after being washed and have full fuel tank. Like ships they are all female, that’s why we men love them.
My car seems to run better after it has been washed and waxed and vacuumed too. I thought this was only happening to me! … lol … Good luck to you @Derek1935
I used K@N you can wash them off and reuse them for life
You will get better mileage with a clean air filter. It’s easier for the engine to breath. More air, more power, better mileage.
knfenimore-No you won’t, you will get more power, not better mileage. If you use the more mower, you will get less gas mileage. A dirty air filter these days acts like the WWII trick of putting a tennis ball under the gas pedal to improve your mileage.
This study shows that a dirty air filter does not affect MPG:
K&N lets more dirt through than a disposable filter.
“This study shows that a dirty air filter does not affect MPG:”
Someone actually thought it was a good idea to spend our tax money on a study that simply states the obvious and confirms what common sense and logic tells us to be true? What a waste of time and money.
There’s no way a dirty air filter can decrease fuel economy. It’s a simple system here. X amount of air enters the engine and the car adds the appropriate amount of fuel Doesn’t matter if the filter is clean or dirty. All that matters is how much air goes in. This isn’t the 1970’s. Cars are pretty smart these days.
“Common sense” and so-called “logic” can be wrong, and have often proven to be so.
I see no reason not to test this particular assumption.
I stand corrected on the better fuel mileage statement as proven in the governments testing, but I was correct as far as decreased power in their 20 to 80 mph test.
“I see no reason not to test this particular assumption.”
I’m not trying to be argumentative, but I find testing this akin to testing the law of gravity.
If you understand how an engine works, there’s no way that a restricted air filter in an otherwise properly functioning gasoline engine will reduce gas mileage.
So silly. Try running a marathon with towels tied over your mouth and nose.
Testing this is no different than testing all the scam mpg add-ons. Obvious they don’t work? Sure, but some folks need a ‘test’ to prove it.
It could be argued that a very dirty air filter increases pumping losses, though it may take lab equipment to measure it.
In the same vein, I am wondering if the OP would post a thread entitled, Soap & Water–Why should I use them?
If you think about it, the reasons for bodily cleanliness are really not very different from the reasons for keeping the intake system of your car as clean as possible.
Preventing disease and preventing mechanical problems are both good ideas…or, at least they are in my humble opinion.
;-))
“Someone actually thought it was a good idea to spend our tax money on a study that simply states the obvious and confirms what common sense and logic tells us to be true?”
Well, @asemaster, it’s not so obvious to a lot of people.
Just look at the opinions on the internet. Most people (including mechanics) insist the filter affects MPG one way or the other.
There are plenty of government studies that spent far more money to prove far more obvious things.
"If you understand how an engine works…"
This is why the government should do studies like this.
Many people don’t understand; then they get ripped off.
Like the Stevie Wonder song goes: “when you believe in things that you don’t understand, then you suffer…”
If a customer’s air filter is so dirty that you can’t even see the light held up behind it, then the shop that sold the customer a new air filter is NOT ripping anybody off
That is my opinion, at least