Hi, I drive a 2001 Astra 1.6 8v and get a loud noise coming the engine when I start it up. (sounds weird, like im driving over rumble strips or on a flat tyre)There used to be a faint noise and was told by Vauxhall that it's the water pump and it needs replacing. This noise is MUCH louder and happened after I was stationary a few days ago, Pressed the aircon button and the car cut out. I started it back up OK and drove it home fine but once I was ready to go out again, the noise appeared. I haven't driven it since 'cause the noise is that loud and embarrasing.I also have an issue with my heaters sounding like they are working but the heat coming out is a joke.Do you think they are all linked or do you have any other ideas?