[johncc]

(Sounds expensive..)

I noticed over the last few days, in this cold weather, when i first start the car I get a rattling noise at idle, from the belt/chain end of the engine.

It's only at idle, and it's only when the engine is cold.

I've never heard chain rattle, so I don't know, but aren't they supposed to rattle when the engine is hot?

I am really hoping its the damper on the belt sticking in the cold...

Any ideas?

 

[rhino2.3t]

yay! i just had that rattling noise when cold as well.. engine out, all new timing and balance gear.. makes it quiet and smoooth, feels like a new lump. the saab smile isnt always cheap to fund, but its a huge bill you'll feel the difference of afterwards!

 

[johncc]

Heh you were meant to say "It's probably nothing, don't worry about it... just turn the radio up."

Ah well... I still think it's the belt, but maybe that's wishfu thinking

Better get it looked at..

 

[billj]

Timing chain will be a rather "solid" rattle. If it's a "tinny" rattle, more like an exhaust manifold heatshield come loose (but there isn't one on the 9000), then I've fixed this twice on the same car. First time, it was a dry bearing on the belt tensioner pulley (it could probably just as easily happen to be the idler pulley and note that they aren't interchangeable). A new pulley fixed the problem. Second time, I checked both pulleys, thinking that perhaps the aftermarket one I'd fitted might have lasted only a year, but they were both fine. I noticed that the pivot on the belt tensioner had a fine halo of reddish dust around it so as a long shot, I sprayed it thoroughly with spray grease. A few weeks later, it is still quiet.

My Aero rattles like a sack of empty cans first thing in the morning, despite a new tensioner pulley a while ago. I'll check the other pulley (I've bought a new one) and I'll also lubricate that pivot while I'm at it.

Or you could just turn up the stereo...

 

[rhino2.3t]

ooh yeah i forgot the reassuring / ignorance is bliss approach.. in fairness my rattle was severe and accompanied by interesting come and go 1500rpm vibration.. also backed up by the last 3years main dealer service history advice 'tensioner replaced timing gear noisy'!
it turned out that the balance cogs had less teeth than an old chicken and were skipping every few turns 're-balancing' the engine as they went. if its a consistent but slight rattle then i'd have gone for pulleys/tensioners first as well and a bit more volume on the stereo..

 

[johncc]

Thanks my ignorance and bliss are hugely enhanced! I'll get it looked at anyway though, since it's probably due a service.

 

[rhino2.3t]

haha and saabs are always more smiley with oil in them (thats the engine, not the cabin - it stains the leather)

 

[Peteysmithy]

Could be a tappet thing, I heard that happens more when the oil gets cold this time of year.

 

[rhino2.3t]

hang on a minute.. in my book tappets are under chapter 3 'annoying ticks' not chapter 7 'expensive sounding rattles'..
posh oil and a sump clean in my old 9k stopped the top end rattle (dont think it had been loved much by the previous owner)

 

[Peteysmithy]

Yes you're right. Sorry. More of a tick tick ticking. Or even a tapping.

 

[SimonF]

Yeah mine makes a tapping noise when really cold outside. I'd just put it down to tappets, but did start to worry when following this link!!

 

[johncc]

Nope, this is definitely not tappet rattle! My old 9K was rattly as a um.. rattle... and this is totally different.

For a start, it's irregular. It's also much tinnier... like Bill J said, more like a loose heatshield or something. And it's not coming from the cam area.

Anyway, it's booked for a service next week now, so all will be revealed in the fullness of time!

As far as chains go anyway, the local specialist told me on the phone that "as long they don't rattle when warm, you're alright for now".

 

[rhino2.3t]

theres no finer comedy than describing engine noises on a forum
ill put a pic of the worst remains of my cogs up eventually for more comedy..
youre right in saying any noise that shuts up once warm is not an immediate bigbill risk - hehe itll just catch you up eventually