Air filter service life

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Because of the responses to the SAE study showing air filter life can easily approach 100k miles and the fact that saying a filter is "dirty" at 10k miles is very subjective, I wanted to see what people really think dirty is?

Would you change this filter? Is it dirty?

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I did some testing and I will reveal the results afterwards.
 
Like the 3,000 mile oil change,air filters don,t cost alot so when in doubt change it out. But a device to measure the filter restriction would take out the guessing. Also where the vehicle is operated and the size of the filter may make a difference in filter life.

[ April 18, 2003, 11:17 AM: Message edited by: Steve S ]
 
Jason, I would change it. A dirty filter could cause your silicon levels to be high on a UOA. Air filters are cheap, no reason to leave them on too long. JMO, Joe
 
But the point of the SAE study is that you will do more harm than good by doing that. Unlike changing your oil too often.
 
Jason,I can't do anything but agree with you the air filter thing is old news to the commercial heavy duty mechanics. I was once called in to the bosses office for the air cleaner change thing about 10 years ago And what was said was it is better to have the customer see the clean air filter than call me about a dirty filter that the customer thinks should have been changed. After telling the boss what a moron he was he called the fleet manager about our conversation and the fleets filters on that model were changed as needed. They had a large filter element and the air pickup was mounted out of the dirt stream .
 
That filter looks fine to me. I bet it still flows well and lets in very little dirt. I think too many people change their air filters too often. Go by the UOA results and see if your performance on your car drops off and then decide when to change the air filter. Especially with K&N air filters (which I'd never run) people clean them far too often (which makes them let in more dirt)
 
Good point Patman about UOAs. After looking at the last oil analysis on my Explorer, Terry asked me if my airfilter had been changed recently, becuase the silicon was high. He was right, my airfilter was factory with 15,000 miles on it. I still think it is cheap insurance. -Joe
 
But a new air filter will allow more dirt to get in, won't it? I think an air filter gets more efficient at trapping dirt as it gets older, the only problem becomes once it restricts airflow to the point of a drop in MPG or a loss of horsepower.
 
Just did a test on my old filter with 20,000 miles vs new. Milage droped average of 1 mpg. Not much but was measurable. My drive to work and back is so consistant it is easy to test milage differences. My milage went from 27 mpg to 30 at 20,000 miles on the car which was break-in of the engine, I believe ,+ the new air filter.
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i think that filter is dirty. i had a filter similar to that, but it was wayy worse. the material was so fragile that it started to fall apart. i look at my filters every 6 months, and change every 12 if it looks bad (bad meanning black). usually my filters go till about 12k before i change them. or when it turns another color.

funnie, i was on frams site and they said they reconmend a filter change every 3k!! Purolator reconmends every 7500k. i wonder if each companies reconmendation of changing the filter is related to the reliability of their product. i think filters are too expensive to be replacing it so soon. here my filters for my car costs 10 bucks, my moms van 15 dollars, my z costs 12 bucks, and my new tl who knows. haha.
 
I believe that filter is way beyond it's service life. Look at the pleat folds. That is where the airflow enters straight in, and both the top and bottom folds are absolutely black. The restriction on this filter must be terrible.....
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[ April 18, 2003, 12:29 PM: Message edited by: TheLoneRanger ]
 
you simply cannot go by a set schedule when dealing with air filters.

while in one condition an air filter may last 100,000 miles, in another condition it may only last 15,000 miles before clogging up.

it depends on where you live, the ammount of pollutants in the air and on and on....


i am currently using my air filter for the last 60K miles on my kia. im getting better than epa fuel efficency for my car.

on my open engine porsche (no hood) the filter is clogged up good after about 5K miles. (the front tires kick up alot of dust and seem to draw it right to the engine)

so it really depends greatly on the variables for which you drive.

my sisters honda has 75K miles on the air filter. its supposed to be white, but its a light tan colour. she still gets 35mpg, the epa published spec. and the intake after the air filter is still clean, so why bother to replace somthing which is not bad?
 
And the winners are...Patman and Cryptokid.

That filter has 25k miles on it.

I performed Frazier Air Permeability testing on new air filter media and this used filter. Permeability only dropped 2.1%. Generally I look for about 40% drop to indicate significant loading. Microscopic examination also supported that. Basically just a light dusting of particulate.
So basically I will leave the new filter on forever. I feel confident leaving it on OVER 100k miles. If I do not see a performance drop, which these results indicate that I won't, then there is no need to change. I will probably change by 10years though, just as a precaution, in case it becomes weak or degraded. But I doubt it will be significantly.
 
Great results Jason! Just like I thought, if the air flow is still good, and oil analysis results show no extra silicon, there really is no reason to change your air filter so often.
 
I think you are just kidding yourself on this one.
Most manufactures recomend changing at 30,000 max.
There is a reason for this. Your air flow will become less and less and your milage will drop for sure. Keep us informed as to how this filter performs at 50,000 as it will be real interesting.
Keep track of your milage. Good luck.
 
quote:

Originally posted by TR3-2001SE:
I think you are just kidding yourself on this one.
Most manufactures recomend changing at 30,000 max.
There is a reason for this. Your air flow will become less and less and your milage will drop for sure. Keep us informed as to how this filter performs at 50,000 as it will be real interesting.
Keep track of your milage. Good luck.


Dude, I tested the airflow. Permeability dropped 2%. That could actually be considered production variance in new material. And that was at 25k miles. (do you think it will suddenly become blinded in those last 5k?)
This is stuff that I do every day. I tell power companies when to change their gas turbine intake filters for example. They have to change right before they become restrictive. With the permeability test you can tell the loading of the media and to put it simply, catch it before the cartridge becomes too restrictive. If the filters are too restrictive, they don't make enough power, they lose money and they don't buy from us anymore.
Maybe it will be interesting for you...but I already know what the result will be.
Good luck? There will be no luck involved. Not needed. Thanks anyway.
 
quote:

Originally posted by Greg:
i would change it.

You guys are killing me
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So I guess you would also change your oil if the analysis had single digit wear metals and a TBN that has not dropped? Sounds like it.
 
Sorry for the jumpy response. Was your response based solely on the original post, meaning you "would have" changed it. Or after reading the entire thread you still would? The former is kind of what I expected; I tended to think people changed their filters too soon and I somewhat confirmed it here. If the later, I don't know what to tell you.
Also, my analysis analogy was not a good example, because contrary to changing your oil too often...by changing the air filter too often, you are doing more harm than good.
 
I might take up the 50K challenge. My 02 Silverado is nearing 30K and the indicator has not moved off of the "clean" end of its scale at all. The manufacturers specifications, as in many things we see, are a case of lowest common denominator and the pervading incompetence of the public in general. (Which is being totally encouraged by the infinitely corrupt legal system and lawyers of the country)
 
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