Boot floor vibrating/resonating?

[Mikeyjp]

so i finally got around to removing the sub ect, but now the boot floor vibrates when the car idles

anyone else have this problem

will a layer of soundproofing sort the problem?

 

[hoolio]

Are you sure it's not the heat shield beneath the floor? Normally sorted with oversize washers on the fixing points.

 

[Carbon Chaos]

Are you sure it's not the heat shield beneath the floor? Normally sorted with oversize washers on the fixing points.

+1 Mine did this

 

[Mikeyjp]

i dont think so, previous owner fitted the ktec sport 2 system with no center box, and the exhaust itself is just making it vibrate

 

[hoolio]

Ok, why do you not think so? If it's the floor the exhaust is obviously vibrating at a frequency that the floor finds damn sexy and responds, that might be difficult to solve, a sack of cement should sort it. Check all fixing/rubber mounts etc.

 

[Badgerman85]

Mines got a ktec system and the boot floor definitely doesn't vibrate, I fail to see how it could what with it being welded in place etc, it its the floor itself that's vibrating I'd be worried that there's something wrong with the back end of your car! I'm inclined to echo hoolios idea of it being the heatshield as these are really prone to rusting out then rattling like mad at certain revs! I'd check the heat shield anyway as it only takes 10 seconds to look under the car and see what's going on!

 

[Badgerman85]

Also no centre box here and decat is on and off the car, no vibrating at all with either...well....not since I fixed my heatshield anyway

 

[Trophy 299]

Pretty much guarantee its the heat shield the large y shaped tin foil piece on the back of the car above the back boxes I have this problem with my Trophy and its had the large washer mod as mentioned before in this post. I bought a new one from Renault in the end and am fitting it next week along with all new mounts.

Mine only vibrates at idle though as the back part at other times does not fall down.

Try looking at the back edge of the heat shield I bet its pulled away from the mountings.

 

[Mikeyjp]

well if its not raining mon, ill have a poke about under it, see whats going on, it only started since i took the weight of the sub out, and if i push down on it slightly it stops

 

[Detailme]

May also be the exhaust mounts. There are several mounts, that bolt to other brackets that finally bolt to the boot floor. Chances are some I the bolts are loose. Chris

 

[eljeffo64]

+1 on the heatshields - was exactly that on mine until the big washer mod was implemented!

 

[bearne1]

Mine is still vibrating at certain rpms despite getting better rear powerflex mounts, a new cat and fitting the larger washers. I cured it on the weekend by wiggling the centre hestshields but no idea how and the problem has come back. Any suggestions on something better to join the two centre hestshields together? They have these metal spring type joiners but they are small and could do with bigger ones if anyone has any ideas?

 

[Rik Perry]

Mine is still vibrating at certain rpms despite getting better rear powerflex mounts, a new cat and fitting the larger washers. I cured it on the weekend by wiggling the centre hestshields but no idea how and the problem has come back. Any suggestions on something better to join the two centre hestshields together? They have these metal spring type joiners but they are small and could do with bigger ones if anyone has any ideas?[/QUOTE

The heat shields crack with vibration.. If you have a good look around the mounts most will be cracked and loose. I removed the whole thing and repaired it and them refitted it sat on areas of silicone to damp it from further vibrations and once the silicone had cured fully tightened the nuts up. Quite as a mouse. Rattle free.

 

[bearne1]

Great good to know, some of the mounts to the chassis were a little loose so will look to replace and retighten.

Do you know what the clips are called that join the two shields together? I will try and get a picture on the weekend.

I played around with them on the weekend and bent the shield slightly near the mid section (Janspeed) and there is little clearance so suspect something is touching albeit slightly. I have seen this come up before on Cliosport as an issue with this exhaust, would upgrading engine mounts stop the overall exhaust movement?

The rear shield has been removed and refitted with the larger 'penny' M16 washers, but the noise is definately more mid / frontal as the rear one was more flapping than rattling before the fix.

 

[Rik Perry]

Could also be a baffle cracked and loose inside the silencers ?

 

[bearne1]

Could also be a baffle cracked and loose inside the silencers ?

I did think this after the cat was replaced but before it was replaced, the problem was cured by me tinkering underneath without doing anything to the exhaust. After fitting the new cat (mechanic) the vibration / rattle seems to have come back albeit at a sligthly different RPM range.

Popped into Renault at lunchtime and ordered a new centre mount and a couple more metal clips to join the heatshields together. I have a suspicion something is running too close to a heatsheild but will have a closer inspection next weekend.

 

[bearne1]

Have had another look this evening and can see no signs of anything untoward, I did find a 16mm bolt that secures the rear shield in place near the mid section that I hadn't put a larger washer so I've replaced that tonight.

1 of the spring clamps at the cat to manifold joint felt loose, is this normal? The kit was replaced with a genuine one from Renault around about 18 months ago.

The cat looks perfectly fitted and the rear section is mounted right and even between the rear bumper slots.

 

[bearne1]

Despite getting 2 garages to look at the exhaust and mountings I have finally found the cat to manifold joint had parts missing so the spring joint was loose, have grabbed a few washers and a thicker bolt so just fitted and all seems good.

 

[Miller]

Nice easy fix it the need then.

 

[bearne1]

I have ordered the parts to fix the joint and make it stronger / future proof courtesy of one of the guys on CS.