Knocking noise in Astra while driving

Discussion in 'Astra' started by BC, Nov 22, 2005.

  1. BC

    BC Guest

    Hi all,

    For the last few years, there is a 'muffled' irregular knocking noise
    in my 1992 Astra while driving straight or turning. It's almost like a
    dead-sounding rattle. It is particularily noticible in cold weather on
    slightly uneven terrain (such as a bumpy road surface), and at speeds
    under 30mph. The noise corresponds with the severity of the bumps. It's
    not the engine, because the sound is still there if I free-wheel with
    engine switched off. It's not as severe in warm weather either. Over
    these years, wear and tear has seen a new exhaust, front shock absorber
    mounts and anti-roll bar bushings installed, but the sound perists just
    the same. It's very different from the sharper sound from C-V joints,
    and anyway, isn't present on smooth terrain while driving straight or
    locking the steering. Driver's door was rattling due to worn hinge, but
    I fixed this and checked other doors also. Sound seems to come more
    from the front. Any ideas on what it might be? Could it be the shock
    absorbers? Mechanic couldn't find anything wrong and the car recently
    passed MOT with no problems. I'd love to solve this puzzle though.

    Thanks,
    Brendan.
     
    BC, Nov 22, 2005
    #1
  2. BC

    R. Murphy Guest

    I'd be interested in this - I have the same problem Untraceable by my local
    VX dealer who claimed it to be front pads 95% worn (miraculously they were
    only half worn hen they looked again a few weeks later), a fractured fan
    mounting (it wasn't), a loose fan mounting (it wasn't), worn links (made
    little difference), and worm shockers (which I can be forgiven for being a
    little sceptical about, given the cost of replacement and the fact that the
    same garage passed it through it's MOT about weeks after this one!)
     
    R. Murphy, Nov 22, 2005
    #2
  3. BC

    Mike Guest

    long shot, but have a (close) look to see if you have a bit broken off one
    of the springs. the last couple of inches can break off with no real effect
    on ride height, but will remain in the mount, banging away at will. you
    really need to put it up on ramps for this though..

    Mike
     
    Mike, Nov 23, 2005
    #3
  4. BC

    adder1969 Guest


    Most probably suspension bushes of some sort (anti-roll bar links?) or
    even a mis-aligned exhaust. I had a car where the exhaust would rattle
    but only when it was raining.
     
    adder1969, Nov 23, 2005
    #4
  5. BC

    Mike Guest

    well the short term solution to that is easy-dont go out in the rain <g>

    I would be inclined to reject the bush idea though, as the OP said it
    recently passed mot.

    Mike
     
    Mike, Nov 23, 2005
    #5
  6. BC

    BC Guest

    Hi,

    One drop-link and bushing was replaced and the other set checked prior
    to MOT which passed. I haven't noticed the effect of rain, but
    temperature definitely plays a role. The sound seems much louder when
    the weather is cold.

    Brendan.
     
    BC, Nov 23, 2005
    #6
  7. BC

    Ivan Guest

    I've got exactly the same symptoms on my H reg 1.7 diesel Astra.

    It's just developed over the last month or so, and like you say when the
    motor really gets warmed up it almost disappears, that is unless I hit some
    really bumpy potholes.

    I checked it out but couldn't see anything physically wrong, mine has also
    recently passed an MoT without any comment on steering or suspension.

    Perhaps it's just one of those things that afflicts older Mark 2 Astra's, as
    I'm pretty certain that if it was a dangerous or serious problem it would
    certainly have been picked up on by now.

    I initially switched from a 1987 1.6 petrol estate to a 1990 diesel version,
    which apart from performance issues was like driving the same vehicle, as ev
    ery problem that afflicted the petrol version was the same on the diesel.
    i.e. wallowing suspension on cornering, understeer, woolly gear change,
    rattling glove compartment lid, fuel gauge with variably unreliable
    readings, screeching blower motor etc.
     
    Ivan, Nov 23, 2005
    #7
  8. BC

    adder1969 Guest

    My Carlton has just passed an MoT yet it sounds likes a drum solo
    driving over rough ground. There are limits as to what will pass an
    MoT and what won't.

    If it's temp related then I'd take a guess that it's some rubber
    component somewhere on the car :)
     
    adder1969, Nov 24, 2005
    #8
  9. BC

    jym Guest

    don't know if this helps but had a similar problem turned out to be loose
    heat shield on the exhaust
     
    jym, Nov 27, 2005
    #9
  10. BC

    R. Murphy Guest

    That one does sound interesting - do you mean the one that you can see as
    soon as you open the bonnet, below the spark plugs, or is there another one?
     
    R. Murphy, Nov 27, 2005
    #10
  11. BC

    jym Guest

    I think it was the one by the cat. the mechanic got under the car with a
    screw and screwdiver in hand anyway and when he came out there was no more
    knocking.
     
    jym, Dec 2, 2005
    #11
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