Rattle on gear change 03 Astra

I have an Astra 1.6sxi on 03 plate with just over 6000 miles on the
clock. When changing up the gears I've noticed a metallic rattling
sound that occurs very briefly. I can get the same sound if at low
revs ( 1200 ) I go from no throttle to my foot flat to the floor in
forth or fifth. I've only noticed it recently as I've had the window
open in the hot weather, you cant hear it with the window closed. As
mentioned it's very brief if a little disconcerting. Anyone else get
this noise? The car seems to run ok. As it's still under warrenty
thought I'd check here before taking it to a dealer and hearing the
immortal line 'but they all do that sir...'

Thanks.

 

As a follow up, a friend who had not seen the car before thought it
was a diesel! I had not noticed before but it is rather noisey on
idle, possibly the tappets. Along with a sort of breathing sound.
Booked in to Vx for Wednesday, hoping its not too serious....

 

I had the same similar noise too in my 1.6 16v Club V plate and that was the
tappets. The Vauxhall dealer just flushed the engine and stuffed magnitec
oil in. The noise was still there though even when that was done. When you
first fire the car up from cold is when you hear it the most before the oil
gets thrown around the engine. Its normal apparently

Matt

 

Had car checked over, apparently no problem with it. The noise is
coming from cam belt area, and apparently is normal for an astra.
However as its under warrenty they are fitting a new cam kit so try
and quieten it down a bit. As for the rattle when changing up the
gears, its pinking. A 'feature' of the 1.6, as you lift off the
throttle the ECU backs off the mixture, as you accelerate again the
mixture is weak and so for a brief second it pinks. One final note,
the fuel line was tight on the body work. The noise of the pump was
resonating down the fuel line which in turn went through the body work
making the engine seem loud inside the car. Moving this has quietened
things down inside.

Kai

 

Check the clips which hold the top of the air filter. We had on in once, and
the customer was complaining of pinking; turned out to be a rear clip
rattling against the bodywork.