Guttural Noise From Under Carriage - 2000 Concorde LXi

Discussion in 'Concorde' started by jaygreg, Dec 12, 2009.

  1. jaygreg

    jaygreg Guest

    Over the past two or three months I've noticed a brief, deep, rumbling
    sound - like a loose heat shield (so I'm told) - coming from under the
    car just just as it accelerated from stop, under load (hill or
    incline). Doesn't last long and is most noticeable when the engine is

    I used to think it was coming from the back so I put a piece of foam
    just behind my rear license plate when I washed the car last and heard
    what I thought was a similar rattle when the sponge caught a corner.
    My imagination must have made it go away...for a day or two. Then I
    began hearing it again.

    It does seem to have grown louder, though, I doubt if the noise can be
    heard by someon outside as I pass them. Today I tried focusing on
    which end of the car it was coming from. With the sound lasting no
    more than three or four seconds, I located it in the front, underneath
    me, and in the back again. In short... I don't know where the hell
    it's coming from other than under the car.

    A friend who has some experience in these matters ruled out a leaking
    head gasket and exhaust manifold gasket; two nightmare that could
    throw my little "renovation project" with this beast into the category
    of "no longer cost justifiable."

    My hopes were renewed when those cradle bolts were replaced without
    incident and I began looking forward to holding onto this car and
    replacing struts and tires knowing full well I'd be faced with an air
    compressor maybe next year or the year after. If this noise turns out
    to be something significantly expensive, I'm going to have to rethink
    everything. Hope that's not the case. I've grown fond of the car over
    the years though I wasn't so five or six years ago.

    Would appreciate receiving a list of things this noise could most
    practically be so I can decide if that vocational school could tackle
    it. I doubt if I can even get it in for them to look at ''til after
    the holidays.
    jaygreg, Dec 12, 2009
  2. jaygreg

    Rob Guest

    it happens very seldom, but a couple times i have heard a growling that
    sounds like its coming from the transmission. it hasn't set the MIL light
    and set no codes, so until it happens again i just take care of it like

    next time you hear it see if it seems to coming from under the floor, close
    to the center of the car.
    Rob, Dec 12, 2009
  3. jaygreg

    jaygreg Guest


    And if it is found to come from under the car close to the center of
    the car? A deep rattle (like a heat shield) from a transmission could
    me??? (bucks)
    jaygreg, Dec 12, 2009
  4. jaygreg

    Rob Guest

    MIL light<<

    And if it is found to come from under the car close to the center of
    the car? A deep rattle (like a heat shield) from a transmission could
    me??? (bucks)"

    if you hear it there, we'll want to determine if it is, or if its from the
    differential inside the trans, or some other item nearby.

    MIL = maintenance indicator light


    And if it is found to come from under the car close to the center of
    the car? A deep rattle (like a heat shield) from a transmission could
    me??? (bucks)
    Rob, Dec 12, 2009
  5. I thought it was Malfunction Indicator Light.
    Ashton Crusher, Dec 12, 2009
  6. jaygreg

    Rob Guest

    ok maybe so......

    Rob, Dec 12, 2009
  7. jaygreg

    Licker Guest

    Could it be a heat shield around any of the exhaust system? Sometimes the
    tack welds come loose.
    Licker, Dec 12, 2009
  8. jaygreg

    News Guest

    Anyone or any small animals missing in the neighborhood?
    News, Dec 13, 2009
  9. jaygreg

    Bill Putney Guest

    Rather than an external heat shield as has been suggested, it may be
    baffles inside a catalytic converter that have come loose and are
    rattling. Common noise on the LH cars.
    Bill Putney, Dec 13, 2009
  10. jaygreg

    Rob Guest

    ah yes. mine makes a ticking sound these days as it warms up. so yeah
    that could be as well.
    Rob, Dec 13, 2009
  11. jaygreg

    jaygreg Guest

    OK. Heat shields and baffles inside the catalytic converter sound like
    two possibilities. I'll use them as starters for the discussion I plan
    to have with the mechanic tomorrow. Thanks guys.
    jaygreg, Dec 15, 2009
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