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Strange humming noise coming from valley pan/bell housing vicinity

Discussion in '6.9L IH & 7.3L IDI Diesels' started by stick_witch, Sep 22, 2020.

  1. stick_witch

    stick_witch Full Access Member

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    Hey guys! I just put in my newly rebuilt, factory IP, fixed the massive oil leak I had with new valve cover gaskets, did a coolant flush and new coolant, and put new oil in and now the rig runs great, AND DOESN’T LEAK!:angel:
    But, now it appears I have a set of new problems...
    Everything runs great, IP is timed more or less (I think its a degree or two too retarded; alright power, no white/blue smoke, but runs pretty quiet),and NO LEAKS:D... but after running it for 30 miles, an ambient humming noise coming from around the CDR valve/bell housing area has popped up at idle (1500-2000rpms). It’s loudest when I’m either under the truck by the tranny or with my head reached over the intake. Nothing seems to change it; clutch in or out, giving it gas, nothing... thinking maybe something is vibrating on the firewall? Doesn’t sound like the IP. Honestly have no idea on this one... its freakin annoying though...

    You guys have any ideas?
     
  2. quickster

    quickster Full Access Member

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    No idea, but if you figure it out ,let me know. My dash sounds like it's buzzing at idle. After I get up to speed I don't hear it. Sounds like something is against the firewall. Mostly when the truck is cold.
     
  3. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    Check all around to see if there's anything that's sitting against the engine or transmission. This will magnify engine vibrations at idle and transfer them to other places. I bought my current truck with headers. Whichever idiot it was who installed them didn't clearance the one on the driver's side for the oil cooler. It was sitting against the rear header and one mounting bolt. It made the most annoying humming noise that I've ever heard at a warm idle. It also rubbed about halfway through that cooler header.
     
  4. Benm2002

    Benm2002 Registered User

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    Probably not this but I just had a vibration noise that sounded like it was coming from the back of the engine and it was my cowl.

    I just install new pedal pushing and a firewall stiffener, after putting it back together and driving for a bit the farthest screw on the drivers side of the cowl decided it to vacate it’s home.
     
  5. stick_witch

    stick_witch Full Access Member

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    Thanks for the responses you guys! Funny enough, the noise has since strangely disappeared... as soon as I engaged a gear and took it for a drive I haven’t heard it since...
    Out of sight out of mind:D
    I’ll just check on the oil cooler and the larger psd oil filter I just put in and make sure the brake line down there isn’t gouging out the new filter.
     
  6. stick_witch

    stick_witch Full Access Member

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    What cowl are you referring to?
     
  7. stick_witch

    stick_witch Full Access Member

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    Thats a cluster f***:idiot:
    I don’t think I’m having that issue, since everything on this rig is pretty stock. Although I did just put in the fl1995 filter so I’m checking to make sure it isn’t contacting the brake line thats there. Also discovered the inspection cover for the clutch is missing one of the mounting bolts so it could be that, but I don’t think its related.
     
  8. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    I wasn't trying to say that you had that exact issue. I was only giving it as my example of how something that was rubbing on something else could make an audible vibration/humming noise.
     
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  9. Benm2002

    Benm2002 Registered User

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    The cowl just below your windshield where your wipers come through.

    There are several screws that go through it but on mine it was the one closest to the drivers fender inside the engine bay.
     
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  10. snicklas

    snicklas 6.0 and Loving It!! Staff Member

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    Also, check the routing of your throttle cable. There has been more that one post about a noise that was the throttle cable laying on something and bringing that noise into the cab...
     
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  11. stick_witch

    stick_witch Full Access Member

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    Hmm... interesting. I did fiddle with that when I took the IP out. I’ll check it, thanks for the hint!


    Sent from my iPhone using Tapatalk
     
  12. riphip

    riphip Supporting Member Supporting Member

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    Make sure the foam isolator on the cable housing is sitting on/against #8 injector feed line. If cable housing is touching feed line, it will cause noise.
     
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  13. IDIBRONCO

    IDIBRONCO IDIBRONCO

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    If the foam is missing, maybe you can wrap the cable housing in some rubber hose to help keep the noise down.
     
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  14. CBRF3

    CBRF3 Full Access Member

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    You might want to check your lifters early ones didn't have needle roller bearings they had a brass bushing that would fail and then all kind of howling whining noise would occur and if not addressed quick would destroy the cam
     
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