Good Afternoon Ladies and Gents, long time reader first time poster. I'm new here so please go easy on me. I have owned a skoda fabia 1.4 2005 (auto) for about a year now, service history good, only 41k on the clock, NEW Mot no advisories and no dash lights on. Since I have had it, no issues, drives great. Until about a month ago an annoying little rattle came about, it has not impaired the overall drive of the car, MPG remains the same handling etc all as normal, but the noise has gotten noticeably louder over the last week

 

When idling it would be intermittent and would be louder at certain rev ranges (2-4k). My best description would be like a not and bolt in a metal tin being shaken around or a simple piece of metal dragging and bumping along the road underneath. I had spent a good half hour searching the forum topics but couldn't find another close to matching my pretty vague issue as I cannot identify where it is coming from to give you all a better idea.

 

Its not from the engine/engine bay and mostly sounds like its front end middle or under drivers side seat. My initial suspicion was a loose exhaust hanger or something like that, after getting the car up on the lift everything was in order, nice and clean hardly any rust to be seen and nothing visibly loose or hanging down. The only thing of note was an ever so slight bit of oil around the sump plug, must be a very minor leak if anything as I check the oil every other week and the levels are always within optimal parameters, as are the other fluids.

 

The sound seemed to travel when going along especially at lower speeds under 25mph, as if there was a piece of metal working itself up and down my exhaust pipe?! I'm sure that cant be the case. Sorry again for the long post, but if anyone has any ideas on what areas to check that the fabia maybe prone to in terms of rattles or common faults please do let me know. If I can give you any further information please just ask and I will respond really quickly.

 

Cheers

 

Steve

I wonder if the catalyst is breaking up and rattling inside the casing. Just a random suggestion but it can happen.

Exhaust heat shield.

I'm thinking heat shield, cat or silencer baffles too. In fact, some years ago my boss's car was getting some exhaust work done, and the fitter called me into he bay and tapped one of the boxes. My response was "Yes, the baffles in that box have broken. Order a new one of those too."

The heatshields are made of alloy so they tend to corrode at the mounting points due to the dissimilar metals and then drop down onto the silencer/pipework 

21 hours ago, nige8021 said:

The heatshields are made of alloy so they tend to corrode at the mounting points due to the dissimilar metals and then drop down onto the silencer/pipework 

 

In my case the shield was fine but the "star" disk retainer thingies corroded away. I was able to unpry the tabs on the heat shield without breaking them and fit new ones.

Thanks very much for all the input thus far chaps. I wonder if TMB is onto something with the catalyst breaking up inside possibly? I have checked what I believe to be all areas around heat shields and nothing moved from the underneath unless there is shield above the pipe as well that can have the same effect? 

 

The other point made regarding silencer baffles, potentially another good idea, the exhaust as a whole doesn't seem to be any louder in terms of decibels or sounding any meatier, my only past experience of that was many moons ago as kids we used to remove baffles from our bike silencers to make them sound bigger while still chopping around at 29mph 😆 I am trying to get an audio clip or video of the sound, but you know what its like, as soon as you try to do it the sound goes away then carries on when you put the phone away! Cheers guys.

 

 

@StevePez Well, I could have been clearer in my earlier post. If you get under the car and tap the box, and then you hear a noise from inside it, that's broken baffles. Unless either the exhaust noise or the rattle actually annoys you, you can leave that until the exhaust needs other work.

@KenONeill thanks buddy I will try this. I am sure you are probably right in either the baffles or heat shields I just need to check them more thoroughly it appears maybe get some new mounts as well if end up doing the work. Whilst it is annoying me, its not terrible, I was just more concerned it was one of those things whereby the longer the leave it the worse it gets and may cause further damage down the line. I will check all this over the weekend when the weather is hopefully a bit better and report back 👍

@StevePez - Since it's become relevant, when I took my boss's car in, the pipe on the back box linking it to the centre had broken, so we knew that needed replaced. The fitter tapped the centre box and I actually said (as near as I can remember and before he said anything) "I'll tell you what you were going to say: 'That rattle is broken baffles and it would be a good idea to replace this too.' I agree, so go ahead and order the parts, and I'll talk to my boss." (I knew he'd agree to spend the money on a company car)

Hey Ken, so got round to having a better look around today. Whether it's good or bad news the rattle is definitely from the Cat. A firm tap on that and I can here something bounce around inside it. I do have to replace the O2 sensors anyway so I figure might as well replace the cat and the sensors at the same time? I'm assuming it would fail it's MOT on emissions but again not sure. MOT not until November. With the rattle being in The Cat, is that something I need to get checked and replaced with more urgency than say a loose silencer baffle? Thanks 

I have a BBZ/BBY downpipe and cat spare. Nearly new with very little use. 

Edited 23 June, 20197 yr by Tech1e

@StevePez - Well, I'd trust anything Techie is prepared to sell as being "fit for purpose". Possible issues with a breaking up cat are:-

1. High emissions; you may well not care about this right now, but it's a possible MOT failure.
2. Blocked exhaust, leading to loss of power and eventually a "failure to proceed".

 

15 hours ago, Tech1e said:

I have a BBZ/BBY downpipe and cat spare. Nearly new with very little use. 

Hi Techie

 

Many thanks for this - excuse my ignorance but is this a like for like replacement for the OEM part or is it an aftermarket piece (will it need any modification to fit to my standard Fabia? I see your in Worcs, possibly a little far for me to collect, what price would you be looking for please buddy? Thanks

12 minutes ago, KenONeill said:

@StevePez - Well, I'd trust anything Techie is prepared to sell as being "fit for purpose". Possible issues with a breaking up cat are:-

1. High emissions; you may well not care about this right now, but it's a possible MOT failure.
2. Blocked exhaust, leading to loss of power and eventually a "failure to proceed".

 

Thanks Ken, appreciate this, I think as the O2 sensors are acting up due to the CAT problem, but will plan on changing these for new on installation of exhaust. Looks like it will need doing prior to MOT so really a case of finding the cash and the time to get it done prior to November. Luckily so far no loss of power or anything, although I'm chewing through petrol s bit quicker than normal

On ‎17‎/‎06‎/‎2019 at 15:27, TMB said:

I wonder if the catalyst is breaking up and rattling inside the casing. Just a random suggestion but it can happen.

Looks like TMB is the winner on identifying the issue Top man (or good guess) Thank you!

 

11 hours ago, StevePez said:

Looks like TMB is the winner on identifying the issue Top man (or good guess) Thank you!

 

 

Cheers and glad you can now get it sorted