Hi everyone, and thanks for reading my post.

Just bought a 2002 Galaxy TDI with 145,000 miles and I think I may have a problem. Now and then I hear a kind of dump valve sound from inside the car when changing gear, is that right? And today I can hear a kind of intermittent rattling/knocking noise to coincide. Are these connected? Sorry if this doesn't make sense to anyone but i`m no mechanic!!

Thanks in advance for any correspondence

It may be best if you can capture the noise, and post it on here, because I'm not sure I'm getting it fully.

Anyway

Now and then I hear a kind of dump valve sound from inside the car when changing gear, is that right?

If you mean from inside the cabin, that must be wrong. If you mean from under the bonnet, it may or may not be ok.

Does it happen on any gear change, or is it just up changes or down changes? And, it doesn't happen if you just depress the clutch?

And today I can hear a kind of intermittent rattling/knocking noise to coincide.

So, this only happens at the same time as the other noise? It never happens when you change gear, without the other noise, or at other times?

Rattling/knocking is probably always an undesirable thing, but it is unclear whether it is a minor problem or a major one. It could be either. It could just be a bit of trim rattling or a clutch, gear linkage or turbo/actuator issue. Maybe, with the 1.9 there are pumpeduse and cam issues that should be considered too, certainly if the engine has been badly maintained, I'm not sure.

if you are up in boost, could be a air leak from from intercooler.... or you could have a larger air filter fitted...... noise could be any of the above..... or something simple as a heat shield for the exhaust? exhaust mounting rubbers? when do these occur?

Thank you for all your replies. I've only done a couple of small journeys since I first posted. I`ve kept the revs down to avoid dealing with the problem, but, `dump valeish sound` isn`t there untill i`m up to temperature and it`s when i`m changing up through the gears when the revs are decreasing. It`s not a `woosh` kind of sound, more of a 4-5 downward notes.??? Makes no sense to me either!!!!!

I'm coming to the conclusion - probably wrongly - that it is something like a leak in the hose to or from the intercooler, which occurs as the engine rocks a bit backwards and forwards as you make a gear change.

With the lack of definitive detail, it is impossible to be sure, but that is currently my first thought. It would be worth having a look around the pipework to see if there are any 'witness marks' that give away where some gas has been escaping.