Strange Noise, Haven't Got A Clue

[louise74]

I wonder if anyone can shed any light on what might be causing this.

I own an 2005 Yaris T3 998 cc when I drive my car from a cold start I don't encounter any problems however, if I park my car up then return to it up to three or 4 hours later and drive when I am idling I have began to notice a strange noise.

I haven't been able to location for the noise but it seems to come from underneath the car and from somewhere in the middle of my vehicle. Its hard to describe the noise, the first time I heard it I thought it was a consequence of road works in the distance until I sussed it was my car, for want of a better way of describing the noise is that its like rocks in a biscuit tin. The noise, once the car has fully warmed back up the noise often decreases or stops.

I have questioned whether it was my exhaust but would be interested as to what others think.

Thank you in advance

[Madasafish]

So a metallic rattle from under the car when restarting after a long rest from driving?

Sounds like something has moved due to heat expansion/contraction?

I would guess exhaust mountings /exhaust hitting underneath... Could be one of the exhaust rubber hangars has broken...

[FROSTYBALLS]

Worst case - could the ceramic part of the cat be breaking up?

[louise74]

Thanks for your replies, I thought I'd add a couple of other bits of info that might help. My fuel usage doesn't appear to have dropped, I filled her up last Wednesday and got over three hundred miles from my tank which is normal, drove to work and back twice (40 miles) drove local (40 miles) then to Nottingham and back (290 miles) and I haven't notice any foul smell coming from my vehicle when I've had my windows down or when I parked up. My car seems to be accelerating fine too.

[Red Yaris 54]

It could be a heat shield on the exhaust that has come loose

[Madasafish]

hmm there is a heat shield under the rear floor - meets the stated location of the noise..

[louise74]

Thank you,

I'll take her to see Mr T, hope it's not going to be too expensive I've already spent close on £500 on my car this year. I am planning on a new car in the next year or so as I need a bigger engine but can't afford it at the minute.