Dirty Air Filter

[dale farley]

I've looked at my air filter a couple times in the last 3 months, and I thought it looked really clean. Decided to change it the other day since it has been a year. When I placed it beside the new one, I realized just how dirty it was.

The sunlight was basically the same on both, but the clean one is reflecting so much more light because it is so much whiter/cleaner. I don't recall ever being on anything but paved roads. I think the moral of this story is don't try to determine how dirty the filter is by just looking at it, but change it routinely for best protection and performance.

[merle&louise]

Dale,

Does your air filter have a gauge that shows yellow when it is clean and turns red when the filter needs changing? Mine has that indicator, and I have been having the coach for 3 years and it still shows yellow (o.k.) Do you think I should change it before the red indicator flips up?

[tdelorme]

Tuga, three years? Change the filter. You are not going to believe how much crap you will find when you pull the cover. Have a vacuum cleaner handy to clean up real good before you install the new filter.
One of our old Foretravels had the filter indicator and after a couple of years of showing green (good) I had a look and the filter was real bad.

[garyde]

Its either once a year or every 12000 miles for me. They get real dirty. The last time I pulled the old one out, fter one year, there was dirt laying in the canister. I wouldn't trust those pressure guages.

[Denny]

Back in the 60's when working at my father's service station, we would hold the trouble light inside the filter and if you could see light through the filter it was ok; no light, replace. Fram even had a device that you could place the filter around a light bulb, cover the top of the filter and press the light switch. MY father would not buy this since it cost money and took up work bench space.

He also thought I lost my mind when I bought my first motor home....he was probably correct.

[dale farley]

Tuga, I don't have the gage on the bus, but I hav one on my Dodge truck. The filter on it gets dirty long before the gage changes to red, so I don't know that I trust them.

I agree with Gary about the 12,000 or once a year. It doesn't take long for a dirty filter to eat up the cost of a new one in increased fuel consumption. More importantly is the accumulation of damage to the engine.

Denny, I've used the light test many times on cars/trucks. I'm not sure it would be effective on the bus filter, since it is so thick.

If a dirty filter causes the loss of 1 mpg, it costs $54 extra every 1,000 miles when diesel is $2.25 per gallon. Doesn't take long to pay for a new air filter.

[adamdegraff]

Can these filters just be picked up at any NAPA? I have such trouble getting items shipped since I am never in one place for very long.

Thanks,

Adam

[Jon Wehrenberg]

The bus is not like a car. At least not like the old cars with carbs.

The computer controls the fuel delivery based on turbo boost which is a result of air flow. As the filter gets dirty it actually is a more efficient filter at the expense of air flow. My point however is a dirty air filter on our buses will not cause black smoke and unburned fuel. It will just impact the horsepower output of the coach. If it performs well there is no harm.

I'm with Tuga.

I have several years on my air filter also. If anyone wants to disprove what I am saying bring a new filter to OKC along with a stopwatch. We can do a timed acceleration run with my old (current) filter in place. Then we will repeat the accelration run with the new one in place.

If the run times are the same I keep the filter for free. If not, I will pay for it. Any takers?

[dale farley]

Jon, That is surprising to me! From some of the other posts I've seen in the last couple years and from what little I know about autos in general, I thought a dirty air filter would impact the fuel mileage and allow more debris to enter the engine regardless of the type fuel sytem.

If what you are saying is 100% correct, then that is good news. I had just as soon change my filter every three years as I had every year, but I'm still a little skeptical about this subject. Why is the DD system any different than any other vehicle that has electronic injection? Are you saying that when the system senses less air flow, it just reduces the fuel flow to match?

[truk4u]

The filter minder is good for the trucks and I have seen them turn to red, but we were putting 120K a year on them at the time and 200K plus for teams.

On the bus, I just blow them out at oil change time and 3 years sounds reasonable to me. Besides, for most, after 3 years your only looking at about 36,000 miles. I just changed mine out because the old one looked real dirty and what's 55 bucks every few years or so.