After reading a few threads on fuel mileage, I decided my mileage was down and not as good as whenthe truck was new and maybe I might try the advice given others about changing the fuel and air filters. I've got an oil change coming up soon, So I got online and ordered filters for everything. Air, Oil and fuel.

Now understand that my last two trucks have been 6.0L with the big donaldson blue air filters. They were expensive to change out. I would open them up a couple of times a year and blow them out with my compressor. But as long as they never looked too dirty, I'd leave them in and replace them every 25,000 or so miles. Usually they just had that light tan dust that blew out pretty easily with a compressor.

So I was really surprised when I opened my 6.7L air filter and found it black. Almost seemed to have a light oil mixed with the dust. This was not something you would blow off with compressed air. I replaced the filter and fortunately they are cheap enough at $12.00 that it's not a big maintenance item.

I notice there is a foam pre-filter. I will have to consider replacing it with each filter change, If the pre filter is allowing that much crud thru, it might need cleaning or replacing. But the clean section of the filter is what is above the pre-filter.

So a couple of questions.
1st Where is the oily residue coming from that made this filter so black? As you can see the part of the filter above the prefilter is cleaner than the part that was in the main box. The dirt was only on the bottom. Up into the pleats, the filter was still clean. All the black is just on the bottom.

2nd what are most of your recommendations for the Pre-Filter. Wash it, replace it. Every filter change or at some other interval.

BTW my truck currently has 15,000 miles on it.

 

Very interesting. If the clean part is the pre-filter which is incoming air and the rest is black then the black residue has to be coming from the intake manifold/motor side.

The prefilter is foam, correct? Cant you just clean it with dish soap and water and let it dry?

 

That's what I thought just wash out the pre-filter, at least for one or two times, If it becomes stiff or brittle, buy a new one.

I doubt the dirt can be coming from the intake side, I thought about blow back, but Because the inside of the and upper portion of the pleats are clean I just don't believe that. I'm just not sure where that crap came from.

 

It almost looks like the stuff you pick up on a dusty country road mixed with a misting of oil.

 

After this post, I pulled both air filters today at 14,702 miles.
I've been stuck in the low 14 MPG when I use to be in the mid 15's so I hope replacing the main air filter is what is needed a bit more often.
I'm planning to swap out both fuel filters at my next oil change simply to see how those look.
Wouldn't the intake tube (whatever it's called) past the filter be oily on the inside if that was blowback?
Mine was as clean as it could be.

The book says we only need to replace the pre-filter (foam) at 45,000 miles.
Now that I know what the foam filter looks like, I won't replace it as often.
There doesn't appear to be a need to.
It was still in decent shape, just full of dust particles if you hit it.
Possibly every other main filter change.

In my opinion, my main filter needed replacement.
Had several large bugs jammed in the pleats, under and stuck to the sides plus the dirt.

Factory main air filter





Factory pre-air filter




New filters - batch one



New foam filter.
Make sure the foam slit is matched with the plastic.
Make sure the foam is formed to the corners.

 

I changed both filters at 12,000 miles..... The cost was not alot of money....since I use my truck to work out of...and average 4,000 miles a month ....both filter will be changed every 12,000 miles....

 

kper05 - it does not look that dirty. Let us know if you see a mileage difference.

 

I just checked my filter the other day and it was nasty also. Painted Horse where did you find a filter for $12?

 

Just a little tip to those of you who are replacing the secondary (foam) filter, especially if you live in a snowy area and have suffered from power loss due to air filter snow packing. Ford has released a updated "low restriction" foam secondary filter. The part number is BC3Z-9601-D

 

Is it possible that the foam pre-filter was at some point "oiled" and that is the source of the residue on the paper pleats? I know in some applications the foam portion of a filter does require an oil film to work right. Just a guess

 

Or, they might have just been following a Dodge for more than 6 miles on the freeway. That will choke up the air filter in a hurry...

 

LOL Epic. so true.
Rut cutter, I bought it from the Desiel Filters Online.com
FA-1902 $11.95

 

Would this filter result in better MPG?

 

I bet this filter would help "alittle" on the performance side also?

 

Thanks for pointing this TSB out. I will be plowing next winter and this is petinent information!