Loud Vibration & Rattling: Not the Exhaust!

Hi there,

No sooner has he finished than it starts all over again.

Something is causing very loud banging noises.
fahren. Erst war es nur leise und relativ wenig. Now it is.
almost constantly, regardless of whether the vehicle is stationary, accelerating, or otherwise.
at a constant speed - and also quite loud.

It's making rumbling and clattering noises, as if something is...
der Auspuffanlage an die Karosserie dran vibriert. My.
My colleague went somewhere and said it's definitely somewhere.
It looks like an exhaust system, but it's not.
We then jacked up the car and inspected the entire exhaust system.
I followed them, but there's no way they could have gotten there.
The noise is very noticeable inside the car, but it's not audible from the outside.
'You can't even say where it comes from. I've already heard it everywhere.'
'I've heard it before, but I've never been able to figure out what's causing the noise. I mean, the sound seems to be coming from the front of the car rather than the back. It's difficult to diagnose because it's not really audible from the outside.'

Kann das der KAT sein, oder das Flex-Rohr? Aber dann würde ich das doch hören wenn ich neben dem Kat liege. Oder die Motoraufhängung? Ich habe alle Schrauben der Motorhalter nachgeschaut. WaThere's nothing lost.

He hasn't lost any performance.

I am grateful for any answer or guess. Something like that totally freaks me out, and I couldn't sleep properly last night .

Thank you.
Arne.

Hi,

Have you ever thought that the rear axle, when the car is not jacked up, might be higher and potentially touch the exhaust?
I used to have that problem too. I jacked up the car, and then there was enough space between the exhaust and the rear axle. I searched for a long time.
It really depends on how your exhaust system is configured, but you should keep that possibility in mind.

Best regards, Rainer.

Dear Rainer,

That can't be the case, because we drove up ramps.
'All four wheels are on the ground in this situation. I may have phrased that poorly. So, if I'm stopped, the handbrake is engaged, and I slightly depress the clutch in first gear, there's a significant 'thump' sound.'

Es stehen bis jetzt in Verdacht: Stoßdämpfer und Befestigung der Servopumpe. Das sind zumindest die Sachen die andere schon hatte wo es ähnlich war. WaWhat do you think?


I am grateful for any further tips, no matter how small.

If there is ever a dieselschrauber.de meetup/party, please let the first round be on me . I swear!

Cheers.
Arne.

Hi Arne,

I've also searched for the cause of clicking noises before and found 2 possible reasons:
1. The fuel line rattles against the diesel filter (Golf 3, 1Z model).
2. The air filter housing rattles because it is only held in place by worn rubber bushings (Golf 3, model 1Z).

Another possibility could be a poorly tensioned timing belt or V-belt, which might start to slap due to uneven rotation (the timing belt touching the housing). If a bearing then fails (e.g., alternator, pump), that could also cause similar noises.

'In the past, my Polo had a problem where the front shock absorbers would make a knocking sound. This was supposedly due to them being loose in their mounts, and the mounts themselves being worn. However, the issue was never fixed and only occurred when driving on uneven surfaces.'

Maybe something here will be helpful. Good luck with your search.

Best regards from OL.

Eike.

Thank you, Eike, for the tips!

It's a very loud vibration, or more like a booming sound. It's so loud that it even drowns out the sound of the diesel engine. You can also feel a slight vibration in your buttocks.

1. That can't be right. I've already checked, and unfortunately, my noise level is too high for that.

2. That's a good idea too, but I have to use a K&N filter because the original air filter housing doesn't fit in the front of the Corrado, and that's where the MAF sensor would need to be located.

Loosely tensioned belts shouldn't be the problem either, since I was underneath the car yesterday while my colleague was making the noise.
Inside, it's very noisy, but there's nothing to hear outside or under the hood, or only a very faint sound. And if it were a belt, I would have heard something, right?

I'm hearing about the shock absorber now for the second time. It would actually make sense, since it's a part that's attached to the body of the car, and therefore the noise is much louder inside than outside.
But it's also making a rattling/vibrating noise when the car is stationary. And that shouldn't be happening if the problem is with the shock absorbers!
'I also noticed this during my lunch break. The noise disappears when taking a right turn, but it's always present when taking a left turn. However, that doesn't necessarily mean anything, as everything in the engine compartment twists and moves during turns, which could temporarily dampen vibrations in other areas.'

What do you think? Please share your opinions. I don't want to take my car to the repair shop.

Thanks,
Best regards,
Arne.

Good evening,

I just came back from the workshop where we discovered that the rear left motor mount was attached with two screws, and one of them was loose! That's why the Corrado was rattling like crazy. Thankfully, the damage has now been fixed.

Thanks again for your help!

Arne.