knocking or rattling under Smart fortwo 450

[Icarus]

can anyone help? There is a loud rattle or knocking we thought from the engine- but possibly the clutch- its there when you stop but as soon as you move off it goes quiet.

thought it may be bearings but it suddenly seemed to happen- one day all was fine - the next there was a big rattle- so not as if anything has slowly worn..is there anything that could have broken or other common problems- its a 2001 Smart 450 and I love it to Bits!!

If its a clutch replacement- can we do it ourselves? Or is it tricky or need special equipment? we have done springs and wheel bearing and stuff

Thanks for any advice
Andrea

[coolfart]

Re: knocking or rattling under Smart fortwo 450

Sounds like something has broke!!!

You are in a better position than anyone on here to see.....have a good look around underneath, and try moving everything....exhaust (make sure it's cold!!), engine, springs, shocks etc......it sounds like something has come adrift as it stops when you move off??

My guess is it could be the exhaust, as that would possibly hit against the valance?

Let us know if you find anything....

[Messerschmitt Owner]

Re: knocking or rattling under Smart fortwo 450

if it was the clutch it would be constant and very very loud. Also your clutch would probably be slipping too.

Stick the car on a set of ramps and switch it on and listen underneath to where the noise comes from!

As Ian says, exhaust, but it could be the engine mounts too

[Thrumbleux]

Re: knocking or rattling under Smart fortwo 450

Something loose getting excited by the low frequency vibration from the engine at idle?
My warning triangle in its plastic case behind the passenger seat used to clang like crazy at idle till I moved it. Only at idle though.

[Icarus]

Re: knocking or rattling under Smart fortwo 450

I'll have a closer look underneath- we did put a screwdriver on to engine housing to find it wasn't coming from there- more from clutch housing..could something be sheered off inside the clutch (a bolt head??) and dropped to bottom? Don't think its exhaust..
clutch not slipping- all working well- noise is very loud til you start to pick up speed...
appreciate all your thoughts..will have another look..but can't see anything obvious on the outside so far...
Cheers
A

[Icarus]

Re: knocking or rattling under Smart fortwo 450

okay- had another look...hubby has good ears for locating- also using screwdriver- its almost definitely coming from clutch housing itself...not external...its more of a knocking that's rythmic with the engine..quite loud.....disappears (or goes very quiet) when you put gas on..
any more suggestions??

I drive most of the time and in automatic and not noticed any difference..hubby drives occasionally and then in manual- he reckons it is very slightly juddery sometimes..but not much....

How easy is to get to clutch? is it an engine out job?? Any ideas??

Smart garage are generally rip off and so far- thru help of clever smarties like yourselves we have managed to fix all the bits that have gone wrong so far- and saved ourselves a fortune- like when we lost powere and thought the turbo had gone- we looked here and found it was a 50p widget that had dropped off!

[heinkeljb]

Re: knocking or rattling under Smart fortwo 450

Clutch can be replaced by any fairly competent DIY fanatic! Just have to have the right tools to undo things with. There are "how to's" available, which give you a general idea of what to do.
Gearbox can be taken off without droping the engine out of the car.

If you are going to take the gearbox off, it would be a good idea at that point to plan on replacing the clutch and thrust bearing system, irrespective of what you find in there, as it a fair amount of work - and I am sure you would not want to have to do it again later in the year if you put back a partly worn clutch!

Just as a possible check to make sure it is clutch side before you delve to deeply in that side, you could take off the belt(s) that run the alternator / Water pump and /or air conditioning pump to eliminate any noise comming from them.

Regards,

John

[Icarus]

Re: knocking or rattling under Smart fortwo 450

Some good ideas there John..don't want to take off more than we have to- or not do the job properly...just wanted to make sure it is the clutch..sort of hoping it might be something simple dropped off inside like a bolt head..or some known common Smartie problem...but spose we're gonna have to have the clutch off anyway .hey ho....good job I've got a motorbike in the meantime!
Cheers
Ax

[heinkeljb]

Re: knocking or rattling under Smart fortwo 450

hi,
Even if it is just something fallen off in the bell housing, you still have to remove the gearbox to get at it!
If you have to go that far, you might as well replace the clutch wile you are there as what could it be? A bolt? If it is the only ones in there are the ones holding the release bearing and arm in place or the ones holding the clutch pack ion place. Eiother way it bouncing around in there will have "knackered" things elsewhere......

Just a thought, you could remove the clutch actuator and using a tourch and magnetic pickup probe, look in the hole where the clutch actuator pin goes into the bell housing to see if you can remove anything small!

Regards,

John

[Thrumbleux]

Re: knocking or rattling under Smart fortwo 450

definitely coming from clutch housing itself...not external...its more of a knocking that's rythmic with the engine..quite loud.....disappears (or goes very quiet) when you put gas on..
any more suggestions??

Someone else will be better positioned to comment, but the dual mass flywheel comes to mind when I read that description.

[Icarus]

Re: knocking or rattling under Smart fortwo 450

dual mass flywheel???? what and where is that? (excuse my ignorance- I'm only a girl!)
if it is that..is it still clutch out?
Cheers

[Thrumbleux]

Re: knocking or rattling under Smart fortwo 450

dual mass flywheel???? what and where is that? (excuse my ignorance- I'm only a girl!)
if it is that..is it still clutch out?
Cheers

http://www.youtube.com/watch?v=YnaXB8q3uzQ

Basically the flywheel is in two concentric parts, with a small amount of rotational movement between the two parts permitted, and controlled by springs.
I'm pretty certain the subject came up in a recent thread and the conclusion was that smarts are fitted with them.

http://www.smartmaniacs.co.uk/forums...+mass+flywheel

And yes, it's a clutch out job if there is a fault there.

[Icarus]

Re: knocking or rattling under Smart fortwo 450

Thanks for all your help guys- will get a new clutch anyway and take it from there...let you what we eventually find! :thanx:

[Mr T]

Re: knocking or rattling under Smart fortwo 450

I'm betting it's the clutch. It sounds very similar to what I had happen & I ended up having a new clutch fitted.:goodlk:
Heres my tale, http://www.smartmaniacs.co.uk/forums...light=knocking

[Ferrina]

Re: knocking or rattling under Smart fortwo 450

Could be the clutch release bearing???