Adam wrote:
Do you know anything about the VW 'mooing' valve? Every time I turn the engine off, I get a mooing noise as if the fuel rail is being pressurised. It's often talked about on T5 forums, but no one seems to know how to cure it

It's probably air being sucked around the 'anti shudder' valve, Adam. That's a vacuum operated butterfly in the inlet that closes on switch off to stop air flow and hence shut the motor down quickly, but especially in the event of a 'run-away'. Yet another 'essential' add-on to Felix's infernal device...
They get mucky and coked up and then don't shut properly, or in some cases stick shut. So they need a good clean from time to time.
But the best way to stop it is sell the van, and buy one with a proper engine...
Who in their right mind would buy a diesel?

That sounds about right. I've just stripped the EGR valve expecting it to coked up, but surprisingly it was clean as a whistle - I think oil burners like being thrashed