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Help!!  Engine noise--serious, Im afraid

Discussion in '80-Series Tech' started by TLCgrappler, Jul 3, 2003.

  1. TLCgrappler

    TLCgrappler

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    I just now noticed on my 96 w 92,000 a constant rattling noise. After lifting the hood and trying to pinpoint the source, I'm discouraged, because it seems to me to be coming from inside the engine, towards the rear.

    It is definitely engine related (and not drivetrain or wheels) because you can hear it in neutral, and it is modulated somewhat by the engine speed. It sounds a lot like my wife's subaru which has a loose exhaust shield, but after poking around in the enginge compartment and crawling underneath on a creeper with the engine running, this is not a shield.....I would have to swear it is something that sounds "loose" internal to the engine, and more towards the rear, transmission area than the front belts, alternator and compressor area. I tried turning the a'c on and off to see if that made a difference, but it seemed not to.

    Am I looking at a main bearing job or whatever its called?? Any help with this is appreciated.
     
  2. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Re: Help!!  Engine noise--serious, Im afraid

    More info. What does it sound like? A tinny rattling, a buzzing, a thumping, ETC. &nbsp:Does the frequency change then the engine speed is increased? Does it change when you put it in gear? More info..........

    A SWAG (scientific, wildass, guess) You may have loose torque converter bolts or a cracked flexplate. (That is total speculation. )
     
  3. Photoman

    Photoman SILVER Star

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    Re: Help!!  Engine noise--serious, Im afraid

    Just something real quick as I am on the way out. An old way we used to use to help pinpoint engine noise was to get a short length of heater hose, hold one end to our ear and move the other around the engine. Please be careful.
    Bill
     
  4. TLCgrappler

    TLCgrappler

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    Re: Help!!  Engine noise--serious, Im afraid

    cdan

    It is most like a tinny rattling, although it is not intermittent....it is constant like buzzing, but not consistently the same, so its most like a tinny rattling. Sounds to me like it would if there were a loose washer somewhere on a nut that had "backed out" partway and was constantly vibrating and slightly shifting position. Very definitely a metalic content to it, and also loud enough to make me think its close to some thin metal to allow it to act like a sounding board.

    Having just listened again, there is a slight buzzing component to it also, but its still more rattle than buzz. Sounds the same in neutral as it does in gear, forward or reverse. frequency increases with enginge speed.

    If it is the torque convertor bolts or the flexplate, where are they??....internal to the transmission?? How seriously could I damage it by continuing to drive? the noise didnt seem to be affecting performance at all.

    Also. I tried the acoustic trick, but I dont seem to be able to isolate a location other than internal rather than alternator or compressor.
     
  5. semlin

    semlin rocker

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    Re: Help!!  Engine noise--serious, Im afraid

    Did you check the heat shields on the exhaust pipes between the catalytic converter and the manifold? One of the clamps on mine came loose producing a noise that sounds very much like yours.
     
  6. cruiserdan

    cruiserdan SupportingVendor Emeritus Supporting Vendor Moderator

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    Re: Help!!  Engine noise--serious, Im afraid

    The flex plate is bolted to the crank shaft and in turn the torque converter bolts to the flexplate. They are in between the engine and transmission. If you get under the vehicle and look to the rear of the engine oil pan you will see a black plastic cover snapped into the front of the bellhousing. This covers the access to the torque converter bolts. Pop the cover and you will be able to see some of the bolts. The engine needs to be rotated to get to all of them in-turn.
     I agree with Simon. Check your exhaust shields also. Your second description sounds more like a sheet metal part or parts shifting. There are also heat shields on the exhaust manifolds. I have seen bolts back out of those also.
     
  7. scottm

    scottm

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    Re: Help!!  Engine noise--serious, Im afraid

    Similar to the heater hose trick, a wood or metal dowel transmits sound even better.  Put one end on the engine, touch the other end to your head near the ear.  Not so good for moving parts!
     
  8. TLCgrappler

    TLCgrappler

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    Re: Help!!  Engine noise--serious, Im afraid

    Well, good news, I think. Car sat overnight, I checked the oil and added a quart to bring it up to the full mark, and started it and the noise was still there.

    Got in and drove about a mile with the windows down listening to my noisy engine and all of a sudden the noise stopped completely as though someone had flipped a switch to turn it off. So for now, I guess I'm happy its gone, and I sure hope it was a stone or something useless rattling in one of the heat shields. Hope it wasnt a missed socket, or worse, some part that worked its way loose that I needed. Anyway, will post again if it comes back. Thanks for the help, guys.