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1986 Bronco 302 and 1996 Bronco 351
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Discussion Starter #1
1996 Ford bronco 5.8 . It’s sort of a high speed, high pitched rattling sound. Sounds too thin and toorapid to be lifters or something like that. Sounds more superficial, kind of on the driver side back of the engine. I have checked the PCV valve and it seems to be firmly seated. I have sprayed some starter fluid to see if there were any vacuum leaks and I don’t detect any. I will note that last week it was in the shop and the mechanic lifted the engine to replace the oil pan gasket. Thanks y’all

 

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Driving Stuff Henry Built
-90 xlt, 351w, e4od, man 1356, 3.55, sag, warn hubs, 35s. -73, 400, np435, d20j twin, 35s
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I think you should use the old shadetree stethoscope. That's where you take a short piece of hose, hold 1 end near your ear, & move the other end around the engine. It works pretty well & should help you locate where the sound comes from. It's sort of like the colder/warmer game as it gets louder in your ear. I'd wonder about an exhaust leak, especially if the engine was raised recently.
 

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If it is not a Bronco, it's just not worth driving.....
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My first guess, it is a bearing that is being turned by your serpentine belt. I would start at the smog pump, then check the alternator, idler pulley and then A/C and power steering.

It doesn't seem to sound like it is inside the engine ( from what you can hear on the video that is... )

Do the hose stethoscope trick @El Kabong mentioned above.
 

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1986 Bronco 302 and 1996 Bronco 351
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37 Posts
Discussion Starter #4
I don’t think it’s an exhaust leak or anything like that because you can still hear it (or at lest something that sounds very similar to it) even after I shut the engine down for about 10 or 15 seconds. It almost sounds like somebody spinning a ratchet . Listen ...

 

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1986 Bronco 302 and 1996 Bronco 351
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37 Posts
Discussion Starter #5
With the stethoscope trick it seems like it’s coming from that area where the evap valves are to the right of the intake Plenum
 

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Sounds like a vacumm leak.
 

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Sounds like the ball in the PCV bouncing all over the place?
 

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95 5.8L MAF XLT, Hedman Shorties/MF SS Y & Muff, E4OD, Man hubs, KYB Quads, 31x10.5x15, 302K miles
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Could it be the Fan hitting the shroud? If they lifted the engine and didn't loosen the shroud it might have popped out of the lower attachment points and is now hitting the Fan. It is hard to tell by the videos. Just a thought!!!
 
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