Another question. I have an Astra 1.8 sxi. I have noticed that in all gears i can hear a kind of humming noise, like a rattling noise from underneath the car near to the engine. Im not sure what it is, its still noticable no matter how hard i accelerate, and it still makes the noise even when im not in gear. I have been told on the other astra forum that it may be a thrust bearing??