Technical GP making hollow knocking on metal noise when stopping and taking off.

[deletemethanks]

Hi guys,

I bought a beautiful GP about a month ago that I'm head over heals in love with - see below for the car picture and my plans with it

Anyway, when I bought it - the car was sitting up for about 5-6 months due to the seller moving to London (I'm presently in Dublin) and it only done 50KM since it passed it's NCT (MOT) so it was literally drove the test center - passed - and came back.

When I test drove it, everything was just fine and dandy but after 2 weeks I noticed a hollow knocking noise from the front and center of the car when taking off (and then it stops after about 10-15KPH and when I'm stopping (as in to a half where you are pushed forward by the force of the brakes). ?It's like someone is at the front of the car knocking it by hand that fades away after 10KPH. I had a local mechanic take a quick look at it and he says it needs new gearbox seals which are being collected today and fitted tomorrow. It's like a rotational noise that I can only hear when taking off because the axel (not hugely car technical) is turning.

My question is, has anyone experience a noise like this before? Could it something as simple as low fluids in my gearbox because of the worn seals or might it be suspension related?

NOTE: What I do know...

* No noise if the car is stopped and I do a full steering lock left or right with City on or off.
* No noise when steerin the car when driving along
* Seems to be particularly common when engine is up to temperature from driving in town, again only when coming to a stop and taking off.
* Car changes gears perfectly, clutch is easy and brakes are fine.
* My GP is the 1.2 5 Door with a 5-Speed Gearbox - 2006 model with only 45,000 miles.

PS: Could it be the exhaust knocking on the underbody or something as simple as locking all nuts and bolts since it was sitting up?

Cheers!

Eamon

 

[keat63]

Although leaking drive shaft seals are apparently common on these cars, they wouldn't cause a knock.
I'd be hard pushed to be persuaded it was leaking seals, unless there's absolutely no oil in the gearbox. If this was the case, there would be a real mess under the car.

Is the knocking noise repetative when rolling.
Ie does it knock, knock, knock and increase or decrease in proportion to the cars speed.

Or is it only a single clunk when accelerating, decellerating.
If so, there's a stabliser bar which runs from left to right under the engine, just behind the sump. Apparently these can warp and cause a rattle or knock on the exhaust.
It's held on with 2 x 17mm bolts, some folks on here have removed it, straightened it and refitted it.
Takes about 15 minutes max. (provided you can get under the car that is.)

 

[deletemethanks]

Although leaking drive shaft seals are apparently common on these cars, they wouldn't cause a knock.
I'd be hard pushed to be persuaded it was leaking seals, unless there's absolutely no oil in the gearbox. If this was the case, there would be a real mess under the car.

Is the knocking noise repetative when rolling.
Ie does it knock, knock, knock and increase or decrease in proportion to the cars speed.

Or is it only a single clunk when accelerating, decellerating.
If so, there's a stabliser bar which runs from left to right under the engine, just behind the sump. Apparently these can warp and cause a rattle or knock on the exhaust.
It's held on with 2 x 17mm bolts, some folks on here have removed it, straightened it and refitted it.
Takes about 15 minutes max. (provided you can get under the car that is.)

It is a knock... knock knock... knock knock... knock knock knock (increasing faster with speed) until I either can't hear because of engine noise or I get up to about 15-25KPH and change gear and then it's gone. That make's me think it's a rolling noise, it's more common when the engine is up to temperature so it's like a part is expanding and then hitting it's metal casing. Today was a cold start and I drove off - no noise at all. When I got to a roundabout a few KM away, it knocks. Always when I stop fully and the car levels out after braking (that's what made me think of the suspension because it's put under strain on both starting and stopping).

It's making me cringe now and embarrassing with passengers.

PS: I put the car in gear the other day with the handbrake on and took my foot of the clutch a bit and let it "rock" and "bounce" and it did make the noises quite a lot.

 

[deletemethanks]

I also just noticed a post from another member, issue sounds familar...

Mine was knocking when pulling away and braking, over speed bumps and bumps in the road. I replaced my top mounts and drop links and it solved every noise.

fiatforum DOT com/grande-punto/238775-replace-anti-roll-bar-drop-links.html#post2507504