Cold Air intake Humming

[NudieWin]

The last.. well I guess almost a year now. Whenever I drive my explorer and its hot out, at some point when I stop at a stop light or in a parking lot for a period of time, or if I shut it off and start it back up without giving it like 3 hours to cool down my cold air intake has the MOST ANNOYING hum ever, and doesnt stop unless I'm on the throttle. Is there a way to prevent that? My coolant is fine and everything, I dont know if it needs more cool air or what, or even how to get more air to it... Help would be great!

 

[aldive]

What intake do you have?

 

[dogfriend]

IAC. Mine does this too. Hot temps make it worse.

http://homepage.mac.com/dogfriend/Explorer/iMovieTheater14.html

 

[NudieWin]

that video is EXACTLY what my truck does... so do I just clean it out and its good to go or what?

 

[m4dc0w]

Just take out the black plastic knob, and throw it away

 

[dogfriend]

I just pull off the black knob (its actually a filter) and clean the felt pieces that are inside. You will have to remove the inner plastic piece to get to the felt; it just pulls out. Cleaning it seems to help for a few months, but eventually the noise comes back when the filters get dirty again

You could also leave the black knob off as suggested, but the filter is supposed to keep dirt out of the IAC valve. As far as I can tell, the passage is to allow the spool valve in the IAC to move back and forth easier.

 

[97SHOgt]

I would just replace it. Only about $40 and solves the problem. I replaced it on my sister's '96 over a year ago and she hasn't heard it. Well worth the money if you ask me. What $40 anymore nowadays...

 

[dogfriend]

You could pull the black knob off, then if the IAC starts getting stuck because of dirt, etc, replace it then.

I haven't replaced mine because the truck still idles correctly; this is the second IAC on my truck, the original failed (truck wouldn't idle) when it was about 3 years old.

 

[NudieWin]

sweet, thanks! I pulled a float in 2 parades this year and half way through both parades it started up... how embarrassing!

 

[Canadadry]

The last.. well I guess almost a year now. Whenever I drive my explorer and its hot out, at some point when I stop at a stop light or in a parking lot for a period of time, or if I shut it off and start it back up without giving it like 3 hours to cool down my cold air intake has the MOST ANNOYING hum ever, and doesnt stop unless I'm on the throttle. Is there a way to prevent that? My coolant is fine and everything, I dont know if it needs more cool air or what, or even how to get more air to it... Help would be great!

I thought I was the only one with a similar problem. It only happens when it is hot out but not all the time. Just occasionally.

I cant exactly tell where it is coming from though, when pop the hood, with all the other noise going on, it is difficult to pin point it, but Ill try to figure out by pulling the plug you guys mentioned to see if it stops immediately. Problem is, it never happens at a "convenient" time so it is hard to trouble shoot.

 

[Canadadry]

I got luck today and the noise started when I was about to leave the grocery store. I quickly jumped out and took the cap off.

Inside the cap, is there suppose to be a filter? And that filter is suppose to be cleaned? I dont want to pull too hard on the center of the inside of the cap for fear of breaking it.

Here is a pic of the inside of my cap.

 

[Lacky01]

you're on the right track!

I personally just stuck the nozzle of a can of carb cleaner and blasted it. let it air dry for a few hours before putting it back on, or it'll scream really loud until it dries completely.

I also took the IAC off and hit that with carb cleaner as well.

I tried running my engine without the cap on it and the idle got rough and it almost stalled. however, it runs awesome with the cap on. does this sound right?

 

[Canadadry]

Thanks I am going to try that, right after I go get the right cleaner.

 

[dogfriend]

Inside the cap, is there suppose to be a filter? And that filter is suppose to be cleaned? I dont want to pull too hard on the center of the inside of the cap for fear of breaking it.

Here is a pic of the inside of my cap.

The center piece of plastic pulls out. I used needlenose pliers to grab and pull - there are two felt pieces under the plastic piece - you can clean them with water or mild solvent - that stops the hum on my truck until they get dirty again - about a year or so.