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Old 08-30-2012, 11:40 AM   #1
fastsoup
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Strange Humming **vids included**

Howdy folks,

So I wanted to adjust my headlight beam last night, turned the ignition to on, went under the hood only to hear this very strange humming coming from a black box that looks to be mounted right by the oil dipstick (video below) Any idea's what this is?

http://s778.photobucket.com/albums/y...t=20120830.mp4


I also have a squeal which is constant no matter what temperature the vehicle is at. Recently changed the rad hoses and pulleys; belt seemed in good condition so I didn't change that. Any ideas?

http://s778.photobucket.com/albums/y...0120830001.mp4


Thanks guys,

F
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Old 08-30-2012, 10:48 PM   #2
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The black box that is making noise is called a DISA flap. You should replace it. The part number is: 11-6-17-544-805. When you take it out you'll see that the flap is most likely separated.

The squealing is hard to isolate on the video. You replaced all pulleys? Sounds like a deflection pulley or alternator. You can use a long screwdriver as a stethoscope to isolate.

Good Luck!
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Old 08-30-2012, 11:02 PM   #3
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sounds like DISA.
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Old 08-31-2012, 05:44 AM   #4
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Is it making that noise with the engine off?
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Old 08-31-2012, 06:12 AM   #5
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I have a humming after I turn the car off too...never really looked to see what it is as my car runs fine, so I figured it was normal...and I still figure that.

Squeal? Yes, as mentioned, if you didn't replace all three pulleys (2 tensioner and 1 idler) then that might be your squeal source.

Pulleys can be installed at a slight angle...if idler's pin doesn't fit in the notch, it'll be off. Any of the other pulleys might be bad too...doublecheck them when the belt is off (PS, ALT, and WP). Use a hose as stethoscope to isolate squeal if you can...as you want to make sure it's not stuff you really need...like alt and wp. Usually the pulleys on these are fine, but in particular with the wp, if it goes, you'll be stranded or worse if you don't know what to do when the car starts to overheat.

Look well. I don't think your humming is an issue...but the squealing sounds like pulley to me. Replace your belts if you don't know they've been done in the last couple of years. Also, when you put the belt back, did you put it back in the same direction? If not, that could cause squealing right there I think.
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Old 08-31-2012, 11:04 AM   #6
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Quote:
Originally Posted by MntnTwisties View Post
Is it making that noise with the engine off?
Yes...
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Old 08-31-2012, 11:08 AM   #7
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Quote:
Originally Posted by dmax View Post
I have a humming after I turn the car off too...never really looked to see what it is as my car runs fine, so I figured it was normal...and I still figure that.

Squeal? Yes, as mentioned, if you didn't replace all three pulleys (2 tensioner and 1 idler) then that might be your squeal source.

Pulleys can be installed at a slight angle...if idler's pin doesn't fit in the notch, it'll be off. Any of the other pulleys might be bad too...doublecheck them when the belt is off (PS, ALT, and WP). Use a hose as stethoscope to isolate squeal if you can...as you want to make sure it's not stuff you really need...like alt and wp. Usually the pulleys on these are fine, but in particular with the wp, if it goes, you'll be stranded or worse if you don't know what to do when the car starts to overheat.

Look well. I don't think your humming is an issue...but the squealing sounds like pulley to me. Replace your belts if you don't know they've been done in the last couple of years. Also, when you put the belt back, did you put it back in the same direction? If not, that could cause squealing right there I think.

The humming is new, unless I have always missed it until the day I decide to correct my headlight aim. The strange thing is that the humming is only there when the car is warm/hot, never cold. Now that I have done some searching, it seems that the DISA somehow regulates torque at low RPM?? Someone correct me if I am wrong. It's also something that you don't want breaking further while still on the vehicle because apparently it can cause some series damage to the block.


I am not 100% that I put the belt on correctly. I will remove and diagnose the pulleys to make sure they were installed correctly. I was just hoping someone could pinpoint the exact issue by just watching the video; wishful thinking I guess.

Last edited by fastsoup; 08-31-2012 at 11:24 AM.
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