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Model specific boards => Golf mk2 => Topic started by: xkaty_h on 24 October 2011, 14:56

Title: Knocking noise when decelerating '91 16V
Post by: xkaty_h on 24 October 2011, 14:56

Hi guys,

The car has developed a knocking noise from within the engine bay somewhere but only when it is decelerating. Under load, normal acceleration and cruising on flat normal roads it's fine.
So far we have checked all visible bolts, engine mounts for tightness. CVs and driveshafts have a little play but not excessive and the car doesn't show any other symptoms of these.
It's been lowered on GAZ coilovers and has had new top mounts, all new polybushes in the bottom arms, anti-roll bar links etc.

Does anyone else have any ideas as to what this could be. I have done a search but there doesn't seem to be a case the same as this.

One thought we did have was that this could have been linked to poor setting up of the throttle cable as there doesn't seem to be a smooth transition when closing the throttle. Our thoughts are that this could cause excessive engine rocking.

Title: Re: Knocking noise when decelerating '91 16V
Post by: rob.043 on 24 October 2011, 15:43

Does the whole car jurk as it makes the noise or is it fairly unobtrusive? is it a particularly loud/heavy noise?

Title: Re: Knocking noise when decelerating '91 16V
Post by: xkaty_h on 24 October 2011, 16:26

The whole car doesn't jerk but it can be felt through the steering wheel. Definitely more of a knock.
It's not particularly loud i.e. people wouldn't stop and stare from the outside looking in as it were.

Title: Re: Knocking noise when decelerating '91 16V
Post by: rob.043 on 24 October 2011, 16:36

Exhaust Manifold on steering rack, if you have a 4 branch on?  But for deceleration its really moving it the wrong way for that.

I remeber looking at your project thread, there's a fair bit of work been done to the car, did you replace diff to crown wheel rivets in the gearbox, they could be failing? Dont know if those symptoms would match though.

What engine mounts do you have, standard or uprated?

Title: Re: Knocking noise when decelerating '91 16V
Post by: pigbladder on 24 October 2011, 19:05

worth checking the wishbone bolts

Title: Re: Knocking noise when decelerating '91 16V
Post by: Ben Lessani on 26 October 2011, 21:42

Continual knocking - or one knock?

Title: Re: Knocking noise when decelerating '91 16V
Post by: dan7 on 02 November 2011, 21:11

Sounds like front engine mount to me? Find a private road, pop the bonnet and get someone to safely hang on over the engine, with all hair/clothes tied up, whilst someone drives reasonably slowly to try and get the noise to happen. I do this and it helps an awful lot. :)

Title: Re: Knocking noise when decelerating '91 16V
Post by: Bigdunc on 02 November 2011, 21:42

my front engine mount went and got a loud clunking noise and no power, another way i was told to test is hand break on and pull car up to biting poing on clutch and watch for engine movement

Title: Re: Knocking noise when decelerating '91 16V
Post by: Wayne on 02 November 2011, 23:45

Sounds like a soft / worn engine mount.