K&n Issues?

rabidscoobie · Oct 12, 2017

Ok have a 2004 Mach 1. Installed a K&N years ago.
About a month ago I cleaned and recharged it but every since then in the early morning hours when its 65* or less outside I get an odd sort of grinding sound coming from the air box. It only makes this noise on cool morning and anything under 1000 RPM's. 1k and up no noise at all.

So any ideas why after a clean and recharge Im getting this sound?

Mattstang04 · Oct 12, 2017

Could be something left loose on or around the air box when put back together. Maybe the problem only manifest in the colder temp because plastic or rubber expands back tight at warmer temps.

Maybe some excess filter oil got somewhere it wasn't supposed to be and creates a cold temp air leak that rattles plastic.

Tough to tell without hearing or seeing it.

If you're using the stock air box make sure everything is correctly aligned and squeezed together by the giant housing clamp. That thing can be awkward to get back together properly.

rabidscoobie · Oct 12, 2017

Thanks for the reply.

Taken it apart several times now and reseated everything nothing helps.
I did a pretty light coat of oil on the filter and left it out all day.

The sound definitely isn't a rattle or suction noise at all. This sound almost as if bearings in an altenator have gone bad. Sounds as if metal against metal grinding. If I take out the filter the sound stops. Ran the car for about 10 mins without filter and all was quiet. Put filter back and immediately sound was there. This is loud enough to hear with windows up and radio on. My car sitting idle in driveway and I hear it in my house.

I'm at a loss here.

rabidscoobie · Oct 12, 2017

I'll try and get a recording of the sound next time.

imp · Oct 12, 2017

Cold contracts, can increase clearance between parts, let them move and rattle. Heat expands, maybe closes up clearance, noise goes away. Metallic parts within Mass Air duct assembly, maybe? imp

rabidscoobie · Oct 12, 2017

I have no clue.
I can take the filter out and put it all back together without filter and no noise. Filter back in and the noise is back.
Checked the duct and blew air threw it with my compressor, nothing came out. Even if there were metal in the duct,there isnt any moving parts.
As for hot and cold effects on materials, Im aware what it does, been in Texas all my life.Seen it destroy all sorts of things.
Filter been in it since I think about 2010,most mileage I put on this car is maybe 4500 a year.

I dunno maybe try and cleaning and another recharge on it, guess if that doesnt work then just go back to OEM style filter.
Not going to spend to much time on a filter.
Just thought maybe I did something wrong with the recharge and was causing this issue.
Maybe the next time my son comes over I'll just jack the filter from his mustang and see what happens.

DSG_Mach · Oct 13, 2017

Thats very odd noise for a filter to make. Maybe its time to upgrade to a cold air intake?

Noobz347 · Oct 13, 2017

Try removing the filter and running the car to see if the noise still exists. Leave the airbox open.

Mattstang04 · Oct 13, 2017

I think there is a metal binding in the filter element. It kinda holds the element together in a cone shape. Maybe check to see of some material has torn, allowing the metal bind to rattle.

rabidscoobie · Oct 13, 2017

As stated above, I ran the car for about 10 minutes without the filter and no noise.
Also inspected filter numerous times since noise has started, no damaged areas anywhere I can see.
I have also left the filter in and taken out the duct that goes to the shaker scoop and still have the noise,just a bit louder.

My main problem with trouble shooting is it will only make noise when cool but right now in my part of Texas it's only cool around 5 am to about 7 am. Neighbors probably don't wanna hear it too much that early...lol.

rabidscoobie · Oct 15, 2017

Ok messed with it this evening since it was cool enough to make the noise.
After pulling it all apart and recharging the the filter again, it still makes the noise but it sounds a different now,not so much grinding. But it now makes the noise with the filter in or out.

View: https://youtu.be/bt7w0LIfSJQ

Now since it made the noise without the filter and is definitely in the duct somewheres. I pulled each piece of the duct apart and found this weird piece inside the duct just behind the MAF sensor. I have a feeling this metal piece does not go in the duct,think maybe previous owner put some gimmick item in there. Well so far I took it out since it just sits inside the duct and now it seems quiet.

Here's the part Im talking about:

imp · Oct 15, 2017

rabidscoobie said:
Ok messed with it this evening since it was cool enough to make the noise.
After pulling it all apart and recharging the the filter again, it still makes the noise but it sounds a different now,not so much grinding. But it now makes the noise with the filter in or out.

View: https://youtu.be/bt7w0LIfSJQ

Now since it made the noise without the filter and is definitely in the duct somewheres. I pulled each piece of the duct apart and found this weird piece inside the duct just behind the MAF sensor. I have a feeling this metal piece does not go in the duct,think maybe previous owner put some gimmick item in there. Well so far I took it out since it just sits inside the duct and now it seems quiet.

Here's the part Im talking about:

Why, that's a SWIRLAROONIE! Makes the air twist around a lot, producing more power. See if you are not lacking power with it outta there!

rabidscoobie · Oct 15, 2017

I have no clue what that damn thing but so far seems to be the noise maker.
Hard to believe I've had this car since 2008 and never saw this thing nor has it made any noise until recent.
Also it seems to idle smoother without it.

Suppose to be cold in the morning so I'll know for sure if the noise is gone without it.

Think I remember many years ago seeing an infomercial of those things, I would never put anything like that in my car

imp · Oct 16, 2017

rabidscoobie said:
I have no clue what that damn thing but so far seems to be the noise maker.
Hard to believe I've had this car since 2008 and never saw this thing nor has it made any noise until recent.
Also it seems to idle smoother without it.

Suppose to be cold in the morning so I'll know for sure if the noise is gone without it.

Think I remember many years ago seeing an infomercial of those things, I would never put anything like that in my car

Glad you found the aggravation source! imp

rabidscoobie · Oct 16, 2017

Thanks every one for the help.
That part was driving me nuts.
Guess when I'd take the filter out and the noise stopped that piece would move or something and making me think it was the filter. Once it made the noise without the filter I knew the filter wasnt the issue.

Anyway thanks again.

Neuron · Oct 16, 2017

OK now I have seen everything, good job on the troubleshooting!

rabidscoobie · Oct 16, 2017

Well this morning I goto work and the noise is back, although not as bad but it's there.

So filter in or out, air box on or off, doesn't matter makes the noise when cool outside, even after motor and under hood is warmed up. I've disconnected the duct goes from shaker to air box and only left the main duct to the throttle body connected and still get noise.

But with filter out if I put my hand just close enough(about 3") to the opening of the duct where the screen mesh is in front of the maf sensor the noise stops. I'm not actually touching anything here,just getting my hand close enough to feel the air pulling in.

So far I've ruled out filter. The sound is the loudest were the air box tube goes into the fender. I tried closing off that tube with no filter and didn't stop the noise either.

So I'm right back to not having a clue and to top it off I'm either getting a cold or just severe allergies.

Mattstang04 · Oct 16, 2017

Hey. I had one of those metal things. I think they were called tornadoes. My dad got one for an old firebird i had and his neon. U think they're more of an obstruction than anything. The noise persisting is concerning though.

The shaker itself isn't overly loose, is it?

Mattstang04 · Oct 16, 2017

Just listened to the video. It kinda sounds like a bearing in one of the accessories is whirring. Get a stethoscope out a long screw driver and listen to the alternator, water pump, power steering, etc.

rabidscoobie · Oct 16, 2017

The shaker was removed while troubleshooting so that's ruled out.
Had the altenator rebuilt last month but noise was before that, regulator was shot.

That's what I was thinking was a bearing. Only does it on cool days and as long as it's cool out it makes the noise,even after driving around for 30 or so minutes. So motor warming up doesn't affect the noise either.
Only very slightly obstructing the air flow into duct with my hand and not touching either the noise stops or revving up to 1k rpm's .
I sprayed a little throttle body cleaner in the throttle body to see if that would make a difference, it didnt.

When I feel better I'll get the scope out again and see what happens.

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