'Screaming' noise under acceleration?

[BurnyC]

OK, so last night I noticed a weird noise under acceleration, so today decided to try and capture it on video and see if anyone could shed any light on it? I appreciate it's not the best video as it's off my iPhone, but I'm hoping it can help in some way!



At first I thought it might be the aux belt, but it ONLY does it under hard acceleration, and comes in about 3,500-4,000 RPM or so...makes no difference if all electrics such as lights, radio, A/C/fans etc. are all off or on, doesn't do it when the car starts up regardless of whats switched on, doesn't do it on full lock etc. It also doesn't do it if I accelerate gently/slowly, or if I rev it when it's out of gear and stationary. Also it had both belts done just over a year/16,000 miles ago with proper Gates etc. kits, so I'm hoping it's not that...!

One other thing that may be coincidence or not, I'm not sure - It didn't do it in the afternoon yesterday, but it did it in the evening - now, in the late afternoon I was driving off a friends driveway, and they have some stupid thing mounted at the end of the drive that I think is for locking the gates into when they're closed - I went over it slowly as they said it was damaged and sticking up more than usual. I cleared it with the splitter, but as soon as it was around the middle of the car I felt it catch on something - I'm not entirely sure what it caught on as it was dark at the time and when I checked this morning I couldn't see anything obviously broken, but didn't have it on a ramp...coincidence?

Any thoughts much appreciated!

 

[Gregor11]

there is a thread on here somewhere of a guy with the very same problem, i cant remember the title of it!! can onyone else? he did sort it in the end and it was nothing massive!!

 

[jesus]

Is it not the exhaust whistle? Mine whistles from 3k onwards.

 

[Gregor11]

mate in the search box type in "noise when accelerating" it'll mean trudging through that lot but you may find some answers!!

 

[BurnyC]

Gregor, I saw the thread, but I think it was 4 years or so ago and couldn't get the sound file to work to see if it was the same thing...sounded very similar though. There was also no definite conclusion as to what it really is...I'm thinking perhaps exhaust based though, especially after catching my car on that thing on my friends drive, but the flange between the DP and the cat doesn't look obviously damaged...?

jesus, it's never made the noise before, so it could be the exhaust whistle but I assumed it wasn't supposed to make this noise?

 

[Gregor11]

i remember now!! i was coming from the cat/downpipe joint!!

 

[BurnyC]

Yes mate, that's the one. That part of the system does seem to be one of the lowest points under the car, so it's possible it caught on that, although damage isn't obvious, but as I said I don't have a ramp...how likely is it for any exhaust damage to only be noticeable under load? Doesn't do it when in neutral and stopped.

 

[Gregor11]

yeah but to be fair, as you accelerate the engine twists, so that will pull the manifold down, so under acceleration it may be forcing a very slight gap, hence your whistle mate!!

 

[SnapMonkey]

Not the missus then?

 

[BurnyC]

Not the missus then?

Maybe my mad skillz in the twisties are getting her excited, who knows. It is an rdotsdot clio after all. However, I'm fairly familiar with the sound of my missus screaming, being the stud I am - no help required from an internet forum on that front...cheers though.

Right, that's this threads allocation of 'missus' jokes used up.

 

[fossie]

Ive got the exact same noise matey, i did think it was exhaust related as well...

Does it sound like its coming from the left side of the engine when your in the car (although obviously its coming from underneath lol)

 

[BurnyC]

Ive got the exact same noise matey, i did think it was exhaust related as well...

Does it sound like its coming from the left side of the engine when your in the car (although obviously its coming from underneath lol)

It kinda does sound like it's coming from the left, yeah. It's hard to place, but middle/left-ish seems to be where it is.

 

[mx1_champ]

trapped child under car ?

 

[BurnyC]

trapped child under car ?

When I'm late, I often tend to rallycross my way through the local park as a shortcut. However, since the incident involving a sunbather, their rather large fun bags and the subsequent removal of my front splinter, I don't tend to travel this way anymore. Therefore the chances of a small child becoming lodged under the car are slim. Thanks though.

 

[BurnyC]

Quick update for anyone who may search in the future...

Just been to the garage, and the clamp that attaches the cat to the rest of the system is very rusted and therefore very loose, looks like it could collapse any minute tbh! The knock on the gate thing probably didn't help either. Getting that replaced tomorrow morning, so will see if that fixes it. If so, happy days!

 

[mantis946]

Movement in the engine could be opening a small gap in the system, hopefully the rusted joint mentioned

 

[M@tt_182]

My exhaust is really weak at that point and the join always fails! I've since refitted the cat for an MOT and it seems to have held up a bit longer than usual.

 

[domsclio182]

Sounds like you need a new cat fitting kit,only buy a Renault one though the pattern one's are shite.

 

[1812lsd]

Sounds like you need a new cat fitting kit,only buy a Renault one though the pattern one's are s**te.

What he said ^ £27ish from Renault. I bought one the other day & its a lot better now.

 

[BurnyC]

Final update (hopefully!). The clamp etc. all got replaced with genuine Renault parts, driven home just now from the garage and seems to have fixed it. Obviously a bit of a weak point so if anyone else has this noise, chances are that's what it is!

Cheers for all the help/advice, much appreciated.

 

[Tigger]

Open the boot and hit her again lol

 

[mark smith87]

The exhaust is prone to movement under acceleration if the engine and dogbone bushes are worn. I've replaced all the mountings on my 172 now and no more movement. Fitted K Tec engine mounts and Powerflex dogbone bush.

 

[BurnyC]

Sigh, it seems this noise has come back. It did it again about a week after getting the clamp done. Took it back, but there was clearly no movement/gaps whatsoever around that area - it was allegedly done with the genuine Renault kit too. It's the original exhaust however, so is there anything else that's likely to have gone in the area of the cat > centre section that could be causing this? I'm stumped if it really isn't the join itself!

 

[Chris32uk]

Ive got the same problem, from about 3k onwards and I have been told it might be related to the air intake, acoustic valve? im clutching at straws though.

 

[BurnyC]

Hmm. It seems you can hear it more if you open the left window than the right, and seems to be coming from that side, but I thought I'd narrowed it down to something to do with the exhaust, as it went away for a week after I had the clamp done...co-incidence though? It also only does it when under load and not when stationary...

 

[George182]

I have a similar squeal, mine is from a hairline crack on a weld on the cat itself.... Tiny tiny hole took me ages to work out what it was!

 

[DeadRabbit]

I have the same issue which turned out to be a crack by the cat had it welded and it went away, unfortunatly my exhaust rubbers were goosed so stuipdly had it welded before they arrived so it cracked again silly me

 

[mikeh]

I'm also experiencing this but it's not as loud as the video.

Did you ever find a solution?

 

[sam55]

Resurrecting an old thread here but wanted to know if anyone can confirm that I have the same issue? I have a video from my trackday a couple of weeks back, if you skip to 4.20 you can hear a similar noise on the straight.

[youtube]7_4RPWz8qu4[/youtube]

Just wanted to know if that's a normal Yozza thing or if it's the same issue mentioned in the OP?

 

[Crazylegs]

Same here, mine makes a horrible whistling noise when you floor it.

I'm running a standard cat and KTEC catback, really doesn't sound nice and makes the car sound really rough to drive.

Is it a gasket issue perhaps? It does sounds very 'blowy' when floored.

 

[davo172]

Crack in the cat 100% had the noise on mine for years common issue

 

[Crazylegs]

Crack in the cat 100% had the noise on mine for years common issue

Thanks for this bud. Do you reckon aye?

Is it a new cat that's required then or is it something an exhaust place might be able to fix?

I'm having a custom made system done in few weeks so I'm wondering if perhaps it's worth asking the guy to take a look at it while the car is with him?

 

[davo172]

Thanks for this bud. Do you reckon aye?

Is it a new cat that's required then or is it something an exhaust place might be able to fix?

I'm having a custom made system done in few weeks so I'm wondering if perhaps it's worth asking the guy to take a look at it while the car is with him?

Crack will be very fine hairline one on cat that opens under acceleration difficult to see just weld it up if poss but may well come back. May be worth power flex dogbone too to reduce engine movements.

 

[Crazylegs]

Crack will be very fine hairline one on cat that opens under acceleration difficult to see just weld it up if poss but may well come back. May be worth power flex dogbone too to reduce engine movements.

Thanks Davo for this, really useful information.[emoji106]

I'm going to a good exhaust place in the morning, will report back with whatever they find. See how it goes.

Many thanks

Marc

 

[Crazylegs]

I took the car to the exhaust place this morning, the clamps holding the exhaust and front of the CAT were knackered so they've replaced them both.

Car sounds a hell of a lot better now, thankfully the CAT is not damaged.