VAUXHALL Astra - Death Rattle?
I have a 2003 Vauxhall Astra 1.4 16v with over 100k miles on clock. It developed a rattle about six months ago. I am working abroad at the moment and my girlfriend who drives it says it has got very loud. Initially it only sounded when at around 2,000rpm or when decelerating, but now it's very apparent at all rpm. I suspect a bad hydraulic tappet. If it is a bad tappet, would it have caused irreparable damage to the head or a valve from not being repaired sooner?
Without checking your car or at least hearing the (rattle) noise from the engine, I can't say what might be causing it. But your suspicion about a noisy tappet would seem the most logical conclusion. If so, it's unlikely that it will have caused any damage to the cylinder head, but it may have done or will do to the valve and, of course, the tappet itself. Indeed, if the tappet is breaking up, it could damage the head, but I doubt it.
I've no idea if your girlfriend is mechanically minded or not, but perhaps she could call into a local Halfords store (or motor accessory shop) and buy a 350ml bottle of Wynns Hydraulic Valve Lifter additive (about £7), then follow the instructions on the bottle. Basically, this involves pouring the contents into the engine oil filler hole. I'm not saying this will provide a dramatic cure, but it should help.