1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

Hearing Strange Noise From Engine Compartment

Discussion in 'Early CJ-5 and CJ-6 Tech' started by mickeykelley, Oct 28, 2018.

  1. Oct 28, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    Well finally got a hundred miles on the rebuilt motor. Things have been going well until yesterday I heard a new noise when I got over 30 miles per hour. It's a rattle kind of sound. The wife said it sounds like the clatter when low on oil but a bit harsher. I've done some experimenting to narrow it down. It sound like coming from the engine and starts at around 2,000 rpm no matter what gear I'm in. When I first started hearing it, if I put in the clutch, it stops. So at stand still I rev the engine up 2,000 and no noise. Took it all the way to about 2,700 and no noise. No drips, no leaks, nothing I've check so far is low. If I get over that rpm and put the clutch in, it goes away. If I put in neutral and clutch out, it goes away. Where should I move to next.
     
  2. Oct 29, 2018
    Rick Whitson

    Rick Whitson Sponsor Sponsor

    I live South of...
    Joined:
    Dec 2, 2014
    Messages:
    800
    Try coasting with the trans in neutral clutch out see if it is in trans or transfer case, just a thought, sounds like it is not in the motor or clutch to me. Good Luck.
     
  3. Oct 29, 2018
    Chilly

    Chilly Active Member

    Joined:
    Mar 12, 2007
    Messages:
    1,000
    Is exhaust close to anything rigid? Any other part of engine, bell housing, tranny close to rubbing?
     
  4. Oct 29, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor

    cordele, Ga.
    Joined:
    Mar 29, 2007
    Messages:
    5,285
    So you know it's not in the engine. Put the transfer case in neutral and run the engine up in RPM and shift the transmission through the gears and see if you can duplicate the sound while sitting still.
     
  5. Oct 29, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    5,880
    Like Chilly says, based on your description I'd suspect a body part vibrating, fan shroud interference, a loose part hitting the frame, etc.
     
  6. Oct 29, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    Good idea, I hadn't thought about that.
     
  7. Oct 29, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    I'm hoping that's all it is. Headed out of town for few weeks then I'll get to crawling under and looking around.
     
  8. Oct 29, 2018
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member Sponsor

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    5,210
    As said verify that it's not something vibrating.

    I have the same issue at about the same mileage since the rebuild. It hit's around 2000 RPM no matter what gear & only there under load after the engine has warmed up. I spent a summer trying to find what was rattling but I now have positively identified it as coming from the engine- I can hear it momentarily while goosing the throttle. Stethoscope is loudest right at the oil pump boss. One day i noticed the oil light flickering at idle- it was 60 PSI right after the rebuild so I parked it for the interim. This winter's project is to pull the pump for inspection & drop the pan to check the rod bearings.
     
  9. Oct 29, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    Today I heard it just a little when I backed out and up a slight hill behind the house, then it was gone. But it's like you said, mostly when it warms up. So I did test today after warming up, staying in first gear as I went to check the mail. No noise up to 2500 rpm.
     
  10. Oct 29, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    5,880
    To me, this seems unlikely to be main or rod bearings, since there should be plenty of oil above that speed. Engine bearing noise also is notably variable depending on load/no-load transitions.

    By the original description, it does not occur unless the clutch is engaged. Therefore, throw-out or transmission bearings may be suspect.

    Or possibly (?) some excess end-play in the crank, eliminated when the clutch is putting pressure to it?

    Still better to hope for a loose accessory...
     
    Last edited: Oct 29, 2018
  11. Oct 30, 2018
    ojgrsoi

    ojgrsoi Retired. Sponsor

    Weatherford, TX
    Joined:
    Dec 30, 2002
    Messages:
    1,783
  12. Oct 30, 2018
    Glenn

    Glenn Kinda grumpy old man Staff Member Sponsor

    Apopka, Fl
    Joined:
    Sep 21, 2002
    Messages:
    8,249
    I'm wondering about the pilot bushing in the flywheel. :susp:
     
  13. Oct 30, 2018
    Hellion

    Hellion Rust covered & junky

    Eastern TN
    Joined:
    Dec 25, 2016
    Messages:
    363
    I was thinking bad throwout bearing. Do pilot bushings eventually start wailing?
     
  14. Oct 30, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    5,880
    Throw-out should not be spinning unless pedal is depressed - but a bad adjustment will spin it all the time and wear it out. Then pushing the pedal will often kill the noise... at first.
     
    cookieman likes this.
  15. Oct 30, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    Didn't see any obvious part rubbing anywhere. Fan and shroud still have clean paint, haven't found anything loose or dangling. So I tried the TC in neutral and ran thru all the gears up to 2800 and no noise. Just trying up and down my on drive as I'm at intentionally not going far from home for awhile. So during that approx 1/4 mile, today no noise thru second but third the drive is too short with twists to get it up to the over 2,000 speeds. More testing and checking when I get back from trip.
     
  16. Oct 31, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    5,880
    I know in my own experience, I have several times been very sensitive to "noises" in a new engine, but in the end it was just an over-abundance of caution.
     
    Dave Deyton likes this.
  17. Oct 31, 2018
    mickeykelley

    mickeykelley Active Member

    Republic of Texas
    Joined:
    Oct 10, 2015
    Messages:
    1,287
    Fingers crossed. I know I have some loss of hearing issues as I've aged, just ask the wife, but I've always been very sensitive to car noises in my known vehicles. Goes back to my days as a kid hot rodder. I hear car noises that are not normal way before others. I hope this is just not one of those times. These things have more noises than you can shake a stick at.
     
  18. Oct 31, 2018
    Focker

    Focker Ran when parked... Runs while moving. Staff Member Sponsor

    Tri-Cities WA
    Joined:
    Aug 18, 2014
    Messages:
    5,520
    License plate?
     
  19. Oct 31, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
    Joined:
    Aug 3, 2003
    Messages:
    5,880
    Loose wheel? Rocks in the hubcaps? Rattlesnake in the glovebox?
     
    Dave Deyton and dozerjim like this.
  20. Oct 31, 2018
    Bowbender

    Bowbender I'm workin' on it! Sponsor

    Northern Minn.
    Joined:
    Nov 14, 2014
    Messages:
    400
    I think that's called "selective hearing", comes in handy sometimes....:D
     
    ITLKSEZ likes this.

Share This Page

New Posts