Noise from engine

2000 FORD EXCURSION
250,000 MILES • 6.8L • V10 • 4WD • AUTOMATIC
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BKIRWAN99
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Need help diagnosing a noise that I have never heard.
Feb 16, 2017 at 7:35 PM
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CARADIODOC
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You need a live person to listen to the noise. If necessary, you can use a stethoscope or a tool called the "Chassis Ear" to help localize the area the noise is coming from.

What are the conditions under which the noise occurs? Is there anything, including changing engine speed, that you can do to affect the noise?
Feb 16, 2017 at 7:59 PM
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JIS001
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If your noise sounds like a loud engine type knocking noise then scan for misfire codes. The cylinder misfiring most likely blew out the spark plug along with the threads.

There is a tool to repair the threads but may cost you around $400.00 to $500.00 plus parts and your time?

But I am just guessing at this point but fairly common with Ford. If you can provide more information like CARADIODOC has stated earlier or post an audio sound then maybe we can try to confirm if that is your actual problem.
Feb 16, 2017 at 9:09 PM
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BKIRWAN99
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Take a look at this video I took. Let me know if this helps.
https://m.youtube.com/watch?v=ti5x1P3WXZ4
Feb 17, 2017 at 11:40 AM
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STRAILER
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Hey,

Thanks for the video it the only way to know what kind of problem you are having. The first thing I would do is remove the serpentine belt and start the engine to see if the noise is still there. If so it sounds like it is the IAC valve which is a common problem with Fords. Place your hand on the valve and see if the noise is coming from there, is so replace the valve. If the noise goes away with the belt off spin each of the accessories to see which one is making the noise.

Please let us know happens so it will help others.

Best, Ken
Feb 17, 2017 at 12:45 PM
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BKIRWAN99
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Ken,

It's not damaging to the engine to run it without belt right? I will check the things you mentioned. How much is an IAC valve? Thanks!
Feb 17, 2017 at 1:18 PM
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BKIRWAN99
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Ken,

Can you hear the noise that I'm referring too? Kind of a high pitch grinding sound. Maybe one of the pulleys is spinning rough. Also noticed car is is idleing inconsistently. It goes up and back down. Thoughts?
Feb 17, 2017 at 1:23 PM
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JIS001
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Remove the belt and start it up as Ken suggested. Should be ok but dont run it too long. But it sounds like a pulley noise maybe the alternator. If noise goes away with belt off then spin each pulley to see whichone feels rough.
Feb 17, 2017 at 2:19 PM
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BKIRWAN99
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Guys,

Check out this video I took after taking belt off and spinning pulleys.

https://youtu.be/saQWiV_BOZ8

Engine started and that noise was gone so am I safe to say it is one of the pulleys ? The one in the video makes lots of noise. Some of the others don't spin well. Should I look to replace all or just the loud one?

Thanks!
Feb 21, 2017 at 7:27 PM
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JIS001
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Replace the loud one.
Feb 21, 2017 at 10:08 PM
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BKIRWAN99
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Will do. What about the others that don't spin that well. They don't stay spinning for more than a second at most.
Feb 21, 2017 at 11:43 PM
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STRAILER
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Yep that's the bad one for sure. One can also tell by the discolored surface where the belt rides.

Let us know what happens

Best, Ken
Feb 22, 2017 at 12:13 PM
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JIS001
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I wouldnt worry about the other pulleys for now unless you want to do it now since the belt is off.

You can also compare the new pulley you installed to see how fast it spins but they normally dont spin very long when you spin them.
Feb 22, 2017 at 1:43 PM
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BKIRWAN99
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Thanks a lot you guys. Just to be clear, the one in the video I posted that spins fast and loud is the tensioner pulley or idler pulley? In my search for new pulley, should I go with Motorcraft ? Or is there a specific brand you would recommend?
Feb 22, 2017 at 4:29 PM
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STRAILER
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O ya Motorcraft is the better choice. I would do them both.
Feb 22, 2017 at 5:35 PM