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Discussion Starter · #1 ·
Hi, I wonder if anyone can help me. I have a 2002 Megane Coupe (mk1, ph2). I have a knocking noise coming from somewhere underneath in the front. It can only be heard at low speeds and only happens when I've driven the car for about 10 minutes once it has warmed up. I was told the rubber sleeves in the fron calipers were shot and needed replacing, so got them replaced but the noise is still there. I was then told that the mounting (dogbone mount) under the engine in the centre needs replacing. The car has only done 24000 miles! The noise is there on even just a mildly rough surface. Also, and I'm not sure if this is related but it occassionally battles to engage first gear, if I release the clutch and then re-engage it it goes in (which I suppose points again to that dogbone mounting). I just don't want to find myself replacing things which don't need replacing. The noise sounds sort of metalic but not entirely (sorry if that doens't make sense, but how do you describe a noise lol). Can anyone offer any suggestions please :)
 

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Hi, I was going to mention either gearbox or engine mount and the dog bone, I believe, is the gearbox mount! It may become apparent after a few minutes driving as it warms up and becomes over squishy [sorry for the technical jargon]! The fact that you have issues in getting first gear may be completely unrelated but might have something to do with the gearbox being slightly out of line due to a worn mount!
 

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Discussion Starter · #3 ·
Thanks Scatz, I suspected it may be the dogbone but wanted to get a second opinion. I thought since it's the bottom mount and the gearbox also seems to hang on that mount that it may have something to do with the gear issue. I'll just take the plunge and get it done then, hopefully my knocking woes will be gone :D
 

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do you notice any movement in the gearstick on accelerating/de-celerating ??
if so that to would also be an indicator to a worn "dog bone" mount...
also sluggish in selecting gears...

the scenic i bought recently had that fault...my local garage replaced it for £72 inc labour !!!

HTH

rgds

Paul
 

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Discussion Starter · #5 ·
do you notice any movement in the gearstick on accelerating/de-celerating ??
if so that to would also be an indicator to a worn "dog bone" mount...
also sluggish in selecting gears...

the scenic i bought recently had that fault...my local garage replaced it for £72 inc labour !!!

HTH

rgds

Paul
Thanks Paul, I haven't actually noticed if the gear stick moves when I accelerate. It is only 1st that doesn't like engaging, it doesn't grind though, it just won't shift, it's like it hits something solid and won't move forward any more. I'm going to get the dogbone mount replaced, I am hoping that it will remedy both problems. I am not concerned about the gearbox, it engages smoothly...phew! I have tried rocking the engine when it is hot to see if the noise presents itself but I can't hear it so assume it must be something to do with the way the vibration feeds to the mount. I'll let you all know the outcome.

Cheers!
 

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is this noise related to road conditions, do you hear it more over bumps and small holes in the road, I had a knocking sound on my wifes Coupe, not a metallic sound but a low knock, it was the outer anti roll bar bushes worn, replacement took a few minutes, silence angain.
Dog bone usually gives you the moving gear stick and a knock or two as the engine moves and bangs against the engine bay as you accellerate or decellerate not very often it stays and bangs all the time if ever, I am guessing drive shafts are ok the rubber boots are still in place, you do sometimes get a knocking sound from them (replaced the wifes as well) usually though this was on a bend or junction when lock was applied you got a knocking sound, my self I would be tempted to look at outer anti roll bar bushes, think I paid £9 for the pair with post of ebay, easyto do, they are held on with a clamp and a 13mm nut n bolt, undo this nut n bolt, clamp drops down ease antiroll bar down with a lever and slide off rubber bush, push new one on push clamp back up push bolt through, wind on nut and tighten, job done! can't miss em they are right under the bottom wishbones.
 

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Discussion Starter · #7 ·
Wow thanks Chris, I haven't done the dogbone yet so will first check the anti-roll bar bushes. My gear lever doens't move around, it does a slight movement as I release the clutch after a gear change but nothing more. CV's are fine, checked them the other day and there is no knocking at all. I had a droplink replaced a few weeks back but it never sorted out the noise. I was then told my brake calipers were loose so replaced the rubber sleeves with a kit, noise still there. The noise is more evident on rough surfaces and you can't hear it above 35mph. I suspect you may be right on this one, outer anti roll bar bushes or maybe still the dogbone, I suppose it's now going to be a process of elimination. Thanks again for the help, I'll let you know the outcome
 

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My wife showed up as quite a rapid knocking sound not that loud some times but always in a straight line and at low speeds usually in town actually, when it is rolling along around 10/15mph seemed to be worse, and is heard when going over small holes not large pot holes, so if you had a few in the street then you got this "knocking" sound a lot, towards the end we even got it over cats eyes, basically you seem to hear it when the front suspension is working trying to smooth out small road inperfections at low speeds, to deep a pot hole you don't hear it nor at higher speeds, so if you get these symptoms you could have the outer bushes going, as said can't miss em just follow roll bar towards road wheel it comes to an end just under bottom arm with a rubber cup/bush type thing, this "thing" is what you need to change, simple to do, I did mine on those metal car ramps after an oil change, no wheels off nothing!
 

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Discussion Starter · #9 ·
Right this just gets more and more complicated. I bought the Outer anti-roll bar bushes and decided to fit them. Well the bolt was so rusty that it got about 3/4 of the way off and the bolt stripped. so now I have a loose bolt which I can't actually get off. So I decided to take the car down to my local garage who I use fairly often for wheel alignment, exhausts etc. Well I told them about the knocking noise and they took the car for a drive. They checked the different bushes and said the bushes including the dogbone and anti roll bar bushes were all fine. They then said it sounded like a CV joint. I don't know what to do now, I'm getting numerous different diagnosis. Any thoughts? I can say there is very subtle feeback through the steering wheel when I hear the noise. However I always thought that CV joint noises are are only there when the steering is turned and in full lock position, my noise is there when I'm even going in a straight line! oh, and the stripped nut is stuck 3/4 of the way undone, I can't even get it back on! :crazy: I have a mechanic coming to change my timing belt on Friday so I will ask him if he can finish the anti roll bar joints. At least that way I have eliminated one thing. I must admit my gut is still leaning towards the ARBB and Dogbone. Any second thoughts? Thanks again for all the advise.
 

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Inner CV....possibly! My inner CV joint on the Scoob had failed/was failing and I was getting a knocking on acceleration and deceleration. See the following video I uploaded to YouTube of my noise and see if it sounds the same. However, the fact your noise only seems to appear after the car warms up doesn't really suggest it's the CV although anything with a car is possible I suppose, they're worse than women sometimes :rofl:

Oh, and please excuse my profanities towards the beginning of the clip, it was due to some stupid bint in a Range Rover that was obviously too large for her to be driving :rolleyes:

You can hear the noise I refer to at the following times (in seconds); 28, 32, 40, 43 & 50. They are though quite obvious!

 

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Discussion Starter · #11 ·
Thanks Scatz, the video was very helpful. My noise doesn't sound anything like that so I suppose you have helped me with that. My noise is more like a "doomp" (sorry I'm not very good at writing sounds), and it is there every few seconds particularly on road surfaces. I think I'll get a second opinion before I fork out £190 on a CV joint! Thanks again, I'll keep searching and when I trace the noise I will let everyone know what this mysterious sound is.
 

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You see, the mention of 'when the car is warm' keeps playing on my mind and I'm pretty sure it's gotta be a rubber bush/mount of some description! Rubber by it's shear physical make up is going to be stiffer when cold and when warmed up is gonna be softer and allow for greater movement, henceforth the thumping when the car is warmed up!

Engine mount, gearbox mount, suspension top mounts (although these might not be effected so much my the engine heat as they are sort of out of the way), ARB's....there are more of which I can't recall at this moment :rolleyes:
 

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Not quite sure how they came to the conclusion that the ARB bushes are ok, when the bolt on one of them is 3/4 undone, this would make this bush behave as if it where worn as it is not locked in place now strange conclusion! CV joint, I would be doubtful myself as you say they mainly play up on lock, if you can hear this joint in a straight line then it will be deafing on a bend. Wheel bearings are another noise not usually a knock though more of a hum/drone in a straight line and are silent on a bend depending on which side (sometimes) not sure on top strut mount never heard one to make a comment, our ARBs knocked no matter what the throttle was doing, heard loudest whilst cruising towards the end, would start to go when car got to around 25mph by the time it was at 30mph not a sound, I think it was silent on bends as well but would come back once on a straight line again (passed its MOT with em like tihs) you obviously have them now so I would change em, as for the bolt hack saw it off and replace it with another 31mm nut/bolt , did you wire brush and spray lube before you tried to get it off, ours didn't look knackerd, was not a lot of play in the bar, but once changed knocking has now gone, have you tried bottom ball joints? they can knock as well, as they play free, you will need a bar to check them ans car on a jack wheel off floor, bar inbetween bottom arm and wheel bearing carrier (knuckle) and try and seperate them (up n down movement), there should be NO movement between them, if there is; ball joint is knackerd, again simple to replace, two 13mm nut/bolts that hold it to bottom arm, and a 14mm (I think) pinch bolt holds it to knuckle. no need to remove strut, no need to remove bottom arm, very easy to do, again did the wife 2 years ago (spilt boots on them), the wifes CV joints use to knock but only when accelerating out of a bend or junction, not in a straight line, boots had poped off and joints ran dry, usual Renault fault, I am guessing you have checked all the nut n bolts on the suspension arm and struts to make sure nothing is lose, wheel nuts tight etc. suprising how many people run around with loose wheel nuts, bring car in for knocking sound, and we find them loose, only has to be a quater of a turn and th erim will move a little, which losens off the rest result - knocking at low speed, just another thought popped into head has it aftermarket alloys on or stock Renault alloys, if after market ones make sure it has its spigot rings in, no rings will make the wheel move on the hub, I bought OZ wheels for the wifes Coupe 5 years back and it knocked and steering vibrated every now and then, turns out after hours of checks the shop that fitted the wheels had forgotten to put the spigot rings in, once they did this knocking and vibration gone! slly bit of information but it might be the key!
 

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Discussion Starter · #14 ·
Right, things get more complex. I had my mechanic come change my timing belt yesterday and so I asked him A. to replace the outer anti roll bar bushes and B. to see if he could find the source of the knock. Well, the anti roll bar bushes turned out to be the wrong ones (they looked identical but the hole was too small). So he replaced the damaged bolt but assured me that the existing bushes are perfect. He spent about 20 minutes checking the suspension and then said, oh look at this, your front coil spring is broken at the top. Well he obviously doesn't carry springs on his arms so I will arrange to get it sorted. When I got home last night I pushed down on the front of the car and you can actually hear the knock but much quieter than it sounds in the car, but an identical noise. I will still get a second opinion just to make sure but he definitely gave the car a more thorough looking at than the last guy. Anyone heard of a broken spring before? I thought the car would have sat funny. He said it is right at the top and not actually in a dangerous place, just irritating. I'll keep you all updated.
 

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Discussion Starter · #15 ·
*sigh* .... I had the front coil spring and shocker replaced. It eliminated a knock, but as it turns out there were 2 knocks simultaneously. Now the know I originally mentioned is still there but not as loud. But here is the bazaar thing. When the car is parked and I push down on the driver side or the passenger side I can hear the knock. I don't even have to push down on it much, the know literally happens when I push down about 1/2 inch! This just gets more and more weird by the day. The strange thing is that it happens regardless of which side the pressure is placed. Any ideas on this?
 

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Hi all, just bought my first renault a couple of weeks ago, it is a 2005 megane oasis 15 dci, it has been running lovely, now it has just developed a knocking noise from the front area very similar to yours but the knocking only ocurs during the following times. 1. when i let my foot off the gas when the engine is not labouring, 2. if i am slowing down in gear and take it out of gear letting it freewheel. 3. when i set off from stationary i get a single clunk/knock. The only times it doesnt happen is when i am excelerating, if i take it out of gear and let it freewheel it knocks but as soon as i apply the brakes to slow down it stops.

Any ideas what it could be??
 

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Discussion Starter · #18 ·
Hi Bohemian100, I would say it sounds very much like an engine mount. My noise is still there but I did get a chance to crawl under the car when my dad was around and got him to push down on the car. I suspect it may be a tie rod / ball joint. The vibration from the noise (when the car is turned off and stationary...obviously ;0) feeds through the nut on the top of the strut, the drive shaft and most metal components so I can't say for sure at this stage but it definitely seems more evident there. I'll still post a reply when I eventually find the culprit
 

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What a dingbat, had some new alloys fitted last week, they hadnt tightened the front driver side wheel nuts properly, i have checked for any damage or wear, everything seems ok, put the wheel back on, tightened the nuts (properly), done a test drive, all is well.

Thanks for the input.
 

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Discussion Starter · #20 ·
Well I'm glad to hear it was something fairly simple, even though it could have been dangerous. Just goes to show, these noises can come from anywhere! No wonder they can be so hard to trace!
 
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