As Haakon has said it is the correct adjustment of the exhaust mounts as well for plenty of clearance. They are very loosely hanging allowing a fair bit of movement i found. Even replacing the engine mounts will (may) alter the exhaust positioning .
Renault Megane Scenic II manual - resonance at 2000+ rpm, particularly as revs drop on gear changing
- Thread starter JohnW
- Start date
Yes, understood and thank you so much. It's so hard to describe noises!! All logic says "exhaust related" but it it is right up front and certainly not like any exhaust resonance I've heard. Not that this means much!!
The cat bolts straight onto the exhaust manifold. There are no leaks of gas at the flexible joint there and the exhaust specialist (note GREY HAIRS
) was pretty sure the noise was not exhaust. He could have sold me a new cat but didn't.
The cat bolts straight onto the exhaust manifold. There are no leaks of gas at the flexible joint there and the exhaust specialist (note GREY HAIRS
) was pretty sure the noise was not exhaust. He could have sold me a new cat but didn't.On coarse chip bitumen only, the Alfa apparently has a buzz somewhere in the cabin that drives Kirsty nuts. But its a frequency my tinnitus ears cant hear, and she cant pin point a direction its coming from to give me a clue!
Noises are annoying
Noises are annoying
There's an argument in favour of not getting too hung up, I do agree, but this one irritates. The car is 2006, which is brand new by my normal standards, so I have expectations......On coarse chip bitumen only, the Alfa apparently has a buzz somewhere in the cabin that drives Kirsty nuts. But its a frequency my tinnitus ears cant hear, and she cant pin point a direction its coming from to give me a clue!
Noises are annoying
Cruising at 100-110 with a CD on you barely notice it.
Crank the stereo up a bit more and you definitely won't hear it
Another thing you can try is getting underneath and hitting things with your hand and see if anything is loose, such as the the exhaust and its heat shields, and any other thing you can think of that is bolted on and can come loose.
Well it is fixed and all concerned are a bit surprised by the cause. It was a tiny bit of free movement between the intermediate bearing on the long drive shaft against the flange that held it in place. So the whole shaft was resonating and it was related to engine speed not road speed. There's no doubt this was the cause. It's like a Rolls-Royce now but with a much better overall design as an automobile.
Thanks for all suggestions! The exhaust is perfect it seems - and the exhaust specialist reckoned it was not that, so he gets full marks as he could have sold me anything to stop the noise.
Thanks for all suggestions! The exhaust is perfect it seems - and the exhaust specialist reckoned it was not that, so he gets full marks as he could have sold me anything to stop the noise.
That's great that you have solved the problem. As you say, the source was unexpected, but seems to have cured the noise.
Even more surprising when you could previously get the noise by revving the engine while stationary (ie, drive shaft not turning), but vibrations and noises move in mysterious ways, or there may have been another source under those conditions. Red herrings are everywhere and can easily lead you up the wrong path.
I notice the wear marks on the plate, like the bearing may have been spinning, but the marks are not new. I wonder if the bearing had previously been replaced but the wear allowed for some movement? How did you correct the problem, did you have a spare plate available?
Don't look too far into it on my behalf, maybe leave well enough alone!
Cheers.
Even more surprising when you could previously get the noise by revving the engine while stationary (ie, drive shaft not turning), but vibrations and noises move in mysterious ways, or there may have been another source under those conditions. Red herrings are everywhere and can easily lead you up the wrong path.
I notice the wear marks on the plate, like the bearing may have been spinning, but the marks are not new. I wonder if the bearing had previously been replaced but the wear allowed for some movement? How did you correct the problem, did you have a spare plate available?
Don't look too far into it on my behalf, maybe leave well enough alone!
Cheers.
Now that it is solved it is interesting and no long infuriating!! I'm sure that was the whole noise all the time. It's been solved with a Loctite adhesive - we'll see how that goes - as they reckoned there was very little free space - as much a mark as major wear. I agree 100% about the slight wear marks being old (i.e. long time happening rather than "happened years ago"). It could be you are right too - maybe a bearing failure/seizure with the previous owner. I actually have the service records so will check that.
David Cavanagh reckons he's never seen one of those plates wear, and he's seen a few Meganes in pieces in his time!
Full marks to Eurocare for finally finding it. Full marks to the exhaust specialist in Osborne Park for not selling me a new cat when he could have done so.
And yes, I'm going to leave well alone now. If the noise returns, we know what it is!
I was thinking it looks like there is substantial wear from possibly a rotational component, but now the wear has corroded over (not shiny), indicating that whatever was wearing against the plate, has not done so for some time, so may have been renewed some time ago.
Or else it has just been rattling away for some time.
Interesting.
Cheers.
I checked what I have of the service records and there's no mention of driveshaft work. Doesn't mean it didn't happen mind you. All it every had was brakes and engine mounts, and an AC fault.
Wow, thats a new one! I've never seen that plate wear - it shouldn't... Probably someone has been in there before and not tightened the two bolts.
Did you replace the plate..? Dammit, I threw one out recently I could have sent you...
Did you replace the plate..? Dammit, I threw one out recently I could have sent you...
Loctite..... There was barely any clearance.
I was pretty surprised! I also agree with you that there's history here that I don't know. My suspicion is that either the shaft (very unlikely) or the bearing (unlikely but possible) has been changed by the first owner. The car was about 10 years old and 120,000 km with one lady owner when we bought it. If the bearing had seized (unlikely) and rotated the outer a bit, this mark might have been the result? Dunno. I have what should be all the service records (that was a battle) and there's nothing ever recorded as done except routine service, a set of brake rotors and an AC repair. It's done 135,000 km now, so low mileage still really.
The "wear" mark is oxidised now, so maybe this supports the idea of an earlier problem. I wondered whether the problem emerged after a repair, they couldn't find it (no criticism there as it was difficult......) and she decided to trade up to a new Koleos. They offloaded the car to another dealer, where I found it. So nice to drive now!!
I do want another plate, that's for sure.
Ha. Thanks so much. PM on the way!
This is the human condition.
Check it hasnt chewed out the actual bearing carrier as well. I've seem both alloy and cast steel versions of this bracket on Megane, the alloy one would be sensitive to a carrier bearing bouncing around in it...
Good idea and thanks.
I definitely threw that one out though...