Thud when I accelerate hard!

[MonkeyVR6 0]

I've recently noticed that when I accelerate hard, really hard, in 1st (maybe even 2nd, I'll have to check) that there is a loud thud/metallic bang...nothing is/has been affected, however after accelerating away in such a fashion when I next brake there is a similar noise, just not as violent. :help:

 

When I brake hard as per normal (emergency or my wife is navigating) there is no noise, when I'm in-gear and I accelerate there is no unusal noises. It just seems to be when I'm accelerating away from a standstill or barely moving.

 

Help chaps...I haven't got a clue what this cold be?!

[bananawhip 0]

What part of the car does it come from?

 

Silly question I know but is everything 100% secure (battery, toolkit/jack, etc) as it just sounds like it's a large object moving from the front of the car towards the back, then back again when you brake.

 

It would only thud in lower gears as higher gears wouldn't give it the shunt it needs, then as cars deccelerate quicker then accelerate it wouldn't take that much of a heavy break to bring it back again.

 

Not very technical but just a thought.

[carpoid 0]

One of your engine mounts ?? Sounds like the noise mine made when it started to go. Do you know if any have been replaced ?

[flusted 0]

sounds like front mount, try putting handbrake on and with bonnet up look for excessive movement by lifting the clutch to biting point

[MonkeyVR6 0]

Right, I'll get someone to check for me - hopefully tonight - to see if I've got a mount going/gone in the engine bay.

 

How expensive are these things to replace? I assume replacing a mount underneath the engine is going to cost a few quid :sad:

[was8v 0]

The bolt through the rear of the front wishbone was loose on my car causing similar symptoms, also a knock over cobbles. This was after having the wishbones changed out.

 

Check all your suspension bolts are torqued up!

[Leonard 0]

Right, I'll get someone to check for me - hopefully tonight - to see if I've got a mount going/gone in the engine bay.

 

How expensive are these things to replace? I assume replacing a mount underneath the engine is going to cost a few quid :sad:

 

Defo sounds like front engine mounts. It is a reasonably expensive job to do with uprated Vibra Tech mounts. However it is worth doing.

 

If it is the mounts you should probably be able to feel a shunt through the drivetrain/gearstick changing from 1st to 2nd

 

Matt

[g60karmann 0]

one way to check for yourself is to open the bonet and try slowly pulling away you should be able to see excessive movement of the engine, but i would put money on it being the front engine mount, my bbm front mount bolt came off twice now :(

[boost monkey 0]

i would place rather large money on this being your front engine mount.

 

My golf did exactly the same - the engine has a large torsion (twist) force back towards the firewall (just watch any turbo'd engine on a dyno) which places a large tension force on the front engine mount.

 

if the bolts has fallen out or the mount is dead, either the bracket (or bracket with mount attached!) will rise up, and then subsequently drop down with a thud or a bang onto the front cross member when you let off the gas or change gear. This is because 1st gear is so short and thus has the largest amount of torsion or twist force applied to the engine.

 

hope that makes sense.

 

Jon.

[bananawhip 0]

OK mine may have been a fairly retarded answer but it was 3am and I couldn't sleep

 

Didn't even think of the engine mount

[Leonard 0]

OK mine may have been a fairly retarded answer but it was 3am and I couldn't sleep

 

Didn't even think of the engine mount

 

Its always good to check the smaller things first! :)

[boost monkey 0]

bananawhip, perfectly plausible mate. I've known batteries to shift around a lot! Mine fell off the perch once and onto the shift tower, couldn't get 1st or 2nd until I stopped an investigated! :nuts: