Knocking under the floor

Lord of Hog · 28th July 2017, 12:54

I've asked this one before but I thought I'd ask again just in case anyone missed it the first time.

I have a knocking/thumping noise coming from somewhere under the floor between the front and back seats. It happens when I go over pot holes, speed humps etc at low speed only and can also happen when changing gear at low speed when the engine is cold and therefore revving a little high and the gear change is not as smooth as with a warm engine. I can feel it when I put my hand on the tunnel to the rear of the centre console, through the armrest and sometimes through the seat. The best description I can give is of something not particularly heavy flapping up and down resulting in a "bump" rather than a "whack". I can't feel it through the floor on either side of the tunnel. I've been underneath and checked for excessive movement in exhaust and fuel tank and found none. It leaves me with the strange idea that whatever is doing it must be in the tunnel along with the handbrake compensator ... or it might even be the handbrake compensator itself.

Before I wait for a dry day and have a go at a bit of carpet lifting can anyone suggest any other possible causes? Not being a suspension expert I don't know exactly what is where and what might touch what if loose or broken. I've tried bouncing the rear end up and down and it seems to settle quickly and quietly enough to suggest that the shockers and springs are doing what they should.

All suggestions gratefully accepted.

Rev Jules · 28th July 2017, 13:05

Could it be the heat shield?

Rev

wullie480 · 28th July 2017, 13:11

Quote:

Originally Posted by Rev Jules

Could it be the heat shield?

Rev

Doubt it those tend to rattle.

I'd have thought exhaust but if you think it's the compensator try driving with a few clicks of the handbrake to see if it goes away once there is tension on the cables.

topman · 28th July 2017, 13:28

Exhaust mounting rubbers?

RPWC · 28th July 2017, 14:05

Quote:

Originally Posted by topman

Exhaust mounting rubbers?

That would be my first thought. Check and see if the hanging brackets are secure

Mickyboy · 28th July 2017, 14:06

Had one a little while back where the exhaust centre section was gently knocking against the cross support by the tunnel
Mick

Ennine · 28th July 2017, 14:40

Quote:

Originally Posted by Mickyboy

Had one a little while back where the exhaust centre section was gently knocking against the cross support by the tunnel
Mick

Me too. Exactly the same. Just close enough to cause contact on heavy bumps. Easily sorted.

Nige

DMGRS · 28th July 2017, 17:55

Same for me too! Was an aftermarket exhaust with a slightly poorer fitment than original.

Knocked its wotsits off over bumps and potholes.

bluemalbert · 28th July 2017, 19:03

What about the banjo shaped Engine mounting? It's exactly in that area. Depending on it's state, it can make a host of noises. The tell tale is usually on clutch take up!

Sent from my SM-J700H using Tapatalk

myfirstrover · 28th July 2017, 21:03

small pensioner ?

28th July 2017, 12:54	#1
Lord of Hog Gets stuck in Rover 75 2.5 V6 in Wedgwood Blue Join Date: Dec 2015 Location: Felbridge, East Grinstead Posts: 982 Thanks: 250 Thanked 294 Times in 206 Posts	Knocking under the floor I've asked this one before but I thought I'd ask again just in case anyone missed it the first time. I have a knocking/thumping noise coming from somewhere under the floor between the front and back seats. It happens when I go over pot holes, speed humps etc at low speed only and can also happen when changing gear at low speed when the engine is cold and therefore revving a little high and the gear change is not as smooth as with a warm engine. I can feel it when I put my hand on the tunnel to the rear of the centre console, through the armrest and sometimes through the seat. The best description I can give is of something not particularly heavy flapping up and down resulting in a "bump" rather than a "whack". I can't feel it through the floor on either side of the tunnel. I've been underneath and checked for excessive movement in exhaust and fuel tank and found none. It leaves me with the strange idea that whatever is doing it must be in the tunnel along with the handbrake compensator ... or it might even be the handbrake compensator itself. Before I wait for a dry day and have a go at a bit of carpet lifting can anyone suggest any other possible causes? Not being a suspension expert I don't know exactly what is where and what might touch what if loose or broken. I've tried bouncing the rear end up and down and it seems to settle quickly and quietly enough to suggest that the shockers and springs are doing what they should. All suggestions gratefully accepted. __________________ Conformity is not morality. Consensus is not truth.

28th July 2017, 13:28	#4
topman This is my second home MG ZT-T 190 Join Date: Jun 2009 Location: Lincolnshire Posts: 5,493 Thanks: 372 Thanked 647 Times in 534 Posts	Exhaust mounting rubbers? __________________ Like being creative? http://www.qwghlm.co.uk/toys/dailymail/

28th July 2017, 14:06	#6
Mickyboy SERVICING AND DEALER DIAGNOSTICS MG ZT CDTI 135 + & MGZT CDTI AUTO 160 & ROVER 75 TOURER CDTI 160 TROPHY YELLOW Join Date: Aug 2013 Location: Hernebay Posts: 4,331 Thanks: 818 Thanked 2,414 Times in 1,141 Posts	Had one a little while back where the exhaust centre section was gently knocking against the cross support by the tunnel Mick __________________ [SIGPIC][/SIGPIC] T4 Owner Jobs done : new UBP, Spy hole mod, Rear hub(wheel bearing),plenum cleaned and emptied, Inline thermostat fitted,Full service, In car Digital tv/DVD Bluetooth Satnav etc, Replaced UBP, Restored headlights,Fixed airbag connection.replaced HP pump,replaced rear light seals,changed intercooler O rings. Jobs to do: ,replace drivers lock,.[/SIZE]

28th July 2017, 17:55	#8
DMGRS Discount MG Rover Spares Rover 75 CDTi, 2x MG ZS180 Join Date: Jun 2011 Location: Hythe, Southampton Posts: 11,320 Thanks: 456 Thanked 3,377 Times in 2,027 Posts	Same for me too! Was an aftermarket exhaust with a slightly poorer fitment than original. Knocked its wotsits off over bumps and potholes. __________________ Your trusted MG Rover specialist! Tel: 02380 001133 / Email: [email protected] We now have a 'chat' function on our site for even quicker replies. Give it a try! Remember - discount code FORUM5 for 5% off

28th July 2017, 13:05	#2
Rev Jules This is my second home Rover 75 Tourer+ Join Date: Mar 2011 Location: Radcliffe on Trent Posts: 10,711 Thanks: 7,308 Thanked 3,929 Times in 2,051 Posts	Could it be the heat shield? Rev

28th July 2017, 19:03	#9
bluemalbert Avid contributor MG ZT 190 Join Date: Apr 2016 Location: Heathrow Posts: 166 Thanks: 109 Thanked 24 Times in 14 Posts	What about the banjo shaped Engine mounting? It's exactly in that area. Depending on it's state, it can make a host of noises. The tell tale is usually on clutch take up! Sent from my SM-J700H using Tapatalk

28th July 2017, 21:03	#10
myfirstrover Posted a thing or two Rover 75 2.0 cdi Join Date: Mar 2011 Location: Newcastle upon Tyne Posts: 1,896 Thanks: 401 Thanked 448 Times in 303 Posts	small pensioner ?