General Loud noise & vibration when raining heavily PLEASE HELP

[portland_bill]

My Panda does this, only in wet weather, usually after a deeper than normal puddle. Some time ago, I found some exhaust mountings looking soft, so replaced them, and the noise seemed to be cured.
But Saturday, the noise arrived again, after a large puddle. All exhaust mountings are nearly new. Under the Panda there are plastic covers over the brake lines running some of the length of the car. These are all secure, but I'm now wondering if the water disturbs them, and then the airflow takes over causing them to vibrate. I don't really want to remove them, and then run through puddles, so am currently pondering how to test this as a theory.

 

[dagdromer]

Is this not caused by the aux belt slipping when driving through the puddle?

 

[steveras57]

Hi just gonna jump in on this! I have recently noticed the same noise and symptom on my own car (2012 500 1.2).

Just for clarity if its the same as the original poster is experiencing what happens is if you drive through a lot of standing or surface water specifically if it floods the rear left side of the car what you get is a sudden loud noise not unlike a kettle boiling that seems to start at the back left side ( where the exhaust tailpipe is located!) then travel forwards under the floor pan to the driver /passenger seat area increasing in volume with a bubbling/.crackling sound accompanied by increased vibration and a lumpy feel to the drivetrain!.

Now then firstly my car has had the front support bracket replaced recently so i know its not a support issue! but and here we go)I have also replaced (myself) the entire length of the exhaust system ie- both front pipe and rear box but as if could not afford Fiats prices (OR quick- fits for that matter!) i bought the pipes from an on-line supplier! -not expecting great quality or long life but have to say at least from a visual point of view they look ok! As i dont recall having the noise or issue with the original pipes on the car i am now suspect that these are the cause of the noise!.

So let me explain! the original back box was the round outlet type , the new one is the square/oval style there is a noticible difference in the back pressure that can be felt from the back box tailpipe in as much as before with the old one the flow felt"strong" and "full" where as with the new one its is "weaker" and less "forceful" this is confirmed when watching the gas flow after a cold start on a cold morning as the gas cloud coming from the pipe is nowhere near as big as it was !.
My thoughts are this!- that the system i have put on is in some way more restrictive( particually the back box!) and what i think happens is as you drive through a large amount of water some of it sprays up and enters the tail pipe flowing into the back box where it BOILS!!! this is the noise we first hear! then the steam created causes a temporary blockage in the pipe thus lowing the systems abillity to flow the exhaust away from the engine! causing the vibrations and labouring feeling! once the water has boiled off and the steam expelled then the flow returns to normal and things are ok! in my case the whole process from start of the noise to return to normal is about twenty seconds! maybe this is what you are having too ?.
Be interested to hear what you think!l and if this is similar to your issues!.

 

[portland_bill]

Is this not caused by the aux belt slipping when driving through the puddle?

Aux belt slipping will normally squeal, often also illuminating the charge warning light. In the UK, most of our puddles are on the left (nearside), with the aux belt on the right.

 

[Nova1734]

Hi just gonna jump in on this! I have recently noticed the same noise and symptom on my own car (2012 500 1.2).

Just for clarity if its the same as the original poster is experiencing what happens is if you drive through a lot of standing or surface water specifically if it floods the rear left side of the car what you get is a sudden loud noise not unlike a kettle boiling that seems to start at the back left side ( where the exhaust tailpipe is located!) then travel forwards under the floor pan to the driver /passenger seat area increasing in volume with a bubbling/.crackling sound accompanied by increased vibration and a lumpy feel to the drivetrain!.

Now then firstly my car has had the front support bracket replaced recently so i know its not a support issue! but and here we go)I have also replaced (myself) the entire length of the exhaust system ie- both front pipe and rear box but as if could not afford Fiats prices (OR quick- fits for that matter!) i bought the pipes from an on-line supplier! -not expecting great quality or long life but have to say at least from a visual point of view they look ok! As i dont recall having the noise or issue with the original pipes on the car i am now suspect that these are the cause of the noise!.

So let me explain! the original back box was the round outlet type , the new one is the square/oval style there is a noticible difference in the back pressure that can be felt from the back box tailpipe in as much as before with the old one the flow felt"strong" and "full" where as with the new one its is "weaker" and less "forceful" this is confirmed when watching the gas flow after a cold start on a cold morning as the gas cloud coming from the pipe is nowhere near as big as it was !.
My thoughts are this!- that the system i have put on is in some way more restrictive( particually the back box!) and what i think happens is as you drive through a large amount of water some of it sprays up and enters the tail pipe flowing into the back box where it BOILS!!! this is the noise we first hear! then the steam created causes a temporary blockage in the pipe thus lowing the systems abillity to flow the exhaust away from the engine! causing the vibrations and labouring feeling! once the water has boiled off and the steam expelled then the flow returns to normal and things are ok! in my case the whole process from start of the noise to return to normal is about twenty seconds! maybe this is what you are having too ?.
Be interested to hear what you think!l and if this is similar to your issues!.

I think you've experienced exactly what I'm talking about!

The mechanics just called me however and he said that the rear wheel has a lot of curb damage and is flat (not sure what that means?) in several areas so he thinks it's that because the sound is worse at higher speeds. Ordered me a new wheel and will hopefully have my car back by the end of the week. I've asked him to check the exhaust, citing your comment, he said its possible and will check.

I'll report back next time it rains heavily I suppose.

 

[steveras57]

Hi I can tell you theres nothing wrong with my wheels or bearings! just checked myself and passed the mot 3 wks ago!

By Flat i think they mean that the wheels been "curbed" and is out of true and therefore unbalanced! what we have experienced is not caused by that! otherwise it would happen all the time not just when its raining!!.

Almost certain its due to the exhaust and water as previously stated!
I am thinking of getting the car hot and pouring a little cold water down the tailpipe to see if it replicates the noise? dont know if it will work with the car not moving though? gonna think on it some more first! let us know your outcomes!

 

[Nova1734]

Hi I can tell you theres nothing wrong with my wheels or bearings! just checked myself and passed the mot 3 wks ago!

By Flat i think they mean that the wheels been "curbed" and is out of true and therefore unbalanced! what we have experienced is not caused by that! otherwise it would happen all the time not just when its raining!!.

Almost certain its due to the exhaust and water as previously stated!
I am thinking of getting the car hot and pouring a little cold water down the tailpipe to see if it replicates the noise? dont know if it will work with the car not moving though? gonna think on it some more first! let us know your outcomes!

Yeah I'm starting to believe it's from the exhaust myself but the mechanic seems convinced it's from the wheel. My tyres and wheel bearings are also in good condition.

If it is from water going into the exhaust and boiling, what are the consequences long term health wise for the car? Could it damage or fault something further?

 

[vexorg]

I dont get why the water part matters to the vibration.

 

[steveras57]

Creating steam which impeads the gas flow from the exhaust! meaning the car labours as the next charge of fuel/ gas struggles to vent from the cylinders. Once the steam /water vents from the exhaust, the flow returns to normal and so does the car!.
its just like if you bung the tailpipe with a rag sooner or later the engines gonna cut out!

 

[Twotone2]

Creating steam which impeads the gas flow from the exhaust! meaning the car labours as the next charge of fuel/ gas struggles to vent from the cylinders. Once the steam /water vents from the exhaust, the flow returns to normal and so does the car!.
its just like if you bung the tailpipe with a rag sooner or later the engines gonna cut out!

Be interesting to know if both yourself and the OP have the same exhaust parts, ie the same brand?

”I've actually just fished out some of the service history paperwork and I had the rear suspension, middle and rear exhaust replaced, replacement bracket from cat to gearbox was included on there with rear springs and shock absorbers. Had it all done in 2020.”

 

[steveras57]

The exhaust i put on both centre pipe and back box was purchased online from CATS 2 U no idea what brand they use! and its not written onto the invoice either so dont know any more than that!".

As for the symptoms causing other issues I am not sure!- LOGIC tells me its just a temporary restriction in the pipe causing the "bogging down and vibrations ! but it sounds 10 times worse cause of the noise!!( which im sure sounds much loader than it actually is!) due to the amplification effect of the resonance under the car also being reflected back from the road! .

As it always clears, and things return to normal after about 15-20 seconds i am fairly sure its not doing any major damage ( might not be doing the exhaust pipes any good though i suppose!?).

To minimise load and strain on the engine !,and any other components my plan is if it happens again to back right off on the throttle to keep the stresses as low as possible!,( by keeping the amount of exhaust gas being forced into the blocked pipe to the minimum amount!) and also try to be objective enough to try to monitor if by doing this the noise dies down any quicker!! and things seem less strained in general!.

If and when i get the chance to do this i will of course post up my findings / feelings for all to see!.

One thing i will be doing if the weather stays dry enough is getting the car up on ramps and physically checking the length of the exhaust system just to be sure theres been no damage or obvious issues with it since the fitting a few months ago? again if i find anything i will let you know!

 

[Nova1734]

Be interesting to know if both yourself and the OP have the same exhaust parts, ie the same brand?

”I've actually just fished out some of the service history paperwork and I had the rear suspension, middle and rear exhaust replaced, replacement bracket from cat to gearbox was included on there with rear springs and shock absorbers. Had it all done in 2020.”

Checked paperwork and it says the centre pipe and exhaust are both Euro flo brand, EXFT4042 and EXFT6087 respectively.

 

[chris3234]

Preha

My Panda does this, only in wet weather, usually after a deeper than normal puddle. Some time ago, I found some exhaust mountings looking soft, so replaced them, and the noise seemed to be cured.
But Saturday, the noise arrived again, after a large puddle. All exhaust mountings are nearly new. Under the Panda there are plastic covers over the brake lines running some of the length of the car. These are all secure, but I'm now wondering if the water disturbs them, and then the airflow takes over causing them to vibrate. I don't really want to remove them, and then run through puddles, so am currently pondering how to test this as a theory.

Perhaps some sort of rag stuffed in the gap to stop any vibrations?

 

[steveras57]

My pipes are European exhaust and catalyst brand c e f t 951 and c e f t 849 reference numbers! dont sound the same but its possible they are sourced from the same central manufacturer and then "own braded" before sale who knows!?.

 

[The Panda Nut]

an I suggest that when this happens, that you lift off the accelerator and very gently touch the brakes and see if that stops it. Also try very gently applying the handbrake keeping the button pressed, and see if this has an effect. Maybe this will change something or help rule out ABS issues.

I wonder also if this could be caused by some panel section filling with water and resonating. I have once seen a car with the back bumper flapping violently at speed so I would check carefully that the bumper is secure all around but particularly along the bottom.

I would then check the heat shields. But while these could start flapping and cause noise I would not think they would cause vibration.

Does your car have a rear spoiler fitted. If so I think something like this might cause such symptoms. A lot of these things are stuck on with double sided tape. If this starts to allow movement when wet it might allow movement and vibtation.

On some 500s with glass rooves, there is a filler panel that has been known to detach. I think some form of body work issue is the most likely cause i#of what you describe. Something is nagging at me on this but its not comi g to mind yet. The only thing I have experieced thats similr is when carrying something on roof bars. I wouldnt even put it past being roof resoance so also try putting a hand up and putting some upward pressure on the roof.

 

[The Panda Nut]

Thinking on this again it brings to mind a problem I had in a 2005 Ford Focus. Exactly the same symptoms. In that case it was aerodynamic. AIr flow caused a violent slapping on the side window and the effect was profound. It felt as is the car was about to disintegrate. Opening the window slightly stopped it completely. This was really irritating and I eventually refused to drive the car (company car) and had it replaced. Should you find something similar let us know as there are a few suggestions to stop such things.

 

[Nova1734]

Thinking on this again it brings to mind a problem I had in a 2005 Ford Focus. Exactly the same symptoms. In that case it was aerodynamic. AIr flow caused a violent slapping on the side window and the effect was profound. It felt as is the car was about to disintegrate. Opening the window slightly stopped it completely. This was really irritating and I eventually refused to drive the car (company car) and had it replaced. Should you find something similar let us know as there are a few suggestions to stop such things.

Think this is why my mechanic seems to think it's from the wheel where its gotten curb damaged.

When the sound and vibration does happen I instinctively take my foot off the accelerator but I've never touched the brakes as I'm usually on the mway so tend to avoid using them unless I have to. Not brave enough to touch the hand brake either in those situations lol.

Back bumper is all secure, no spoiler fitted, it does have a glass roof but there are no lose bits or bobs.

 

[The Panda Nut]

Aero things need only the tiniest amount of movement and that can start panel vibration that can be extrodinarily loud. I had a sheet of plywood on the roof of my panda and started vibrating at 25mph. The vibration split the sheet n half by the time I stopped. There was a recent post where the front panel in front of the roof detached on a 500. If something like this or indeed were loosened by water acting on points of contact with the car it could be at the root of this.. I would try gaffa taping the edges of the glass panel and the filler panel as this would prevent air getting under thes and water entering as well. If you get any change in the behaviour with the panel gaps sealed you will be able to eliminate this as a possible source of the problem. It seems that this is most likely an aero issue or bearings of some sort. I cant see how water could interfere with bearings to bring baput the effect you describe, But one faulty panel retainer most certainly would. With a glass roof and plastic filler panel there is some potential. Something that is rubber to metal might be quite stable when dry but be able to move when wet.

 

[steveras57]

My back bumper totally secure! no spoiler!,& no glass in roof so its not that either! when i check underneath i will look for anything loose at all!- but even so that would not explain why it needs a big puddle and/or large amount of spray to cause noise and vibrations! which i m o are coming from UNDERNEATH the car for sure!.
If it occurs again whilst driving will try the handbrake test if safe to do so!

 

[steveras57]

Id be interested in a more detailed explanation from your mechanic as to why they think a damaged wheel would only cause "noise and vibration" under very specific conditions!!? ie driving through heavy rain and/or large puddles of standing water!
.
Surely if the wheel is that bad then surely it would be generating a problem ALL THE TIME!? and not just happening when a situation involving water is present!.

The theory just dont make sense to me! but i do accept that they have never experienced the problem so are basically working on supposition!