Citroen XM Forum

That is indeed the drain plug. Try unscrewing it then probing with a bit of stiff wire.

Thanks Dieselman. I am speaking to a french company who may be able to supply a set of silicon water pipes for my car. However, they cant confirm this from my vin number. I am not sure why but there system only brings back the header tank. They are asking for more info. I have taken photos of the pipes but does anyone have a parts diagram for the series one V6? I have tried to find one on the internet but have not yet found one. I know it’s a long shot and a full set of silicon pipes will be expensive but it seems worth looking at. Cheers

This should be correct for your car.
In general the original Hutchinson brand rubber pipes used by Citroen are very good quality and normally last well.

Thanks for the diagram, I am not desperate for new water pipes, they look pretty decent and are not leaking but I will explore the possibility of changing them for silicon. I went back to flushing out the cooling system today. I opened the drain valve, after removing the expansion tank cap and taking the top hose off the radiator and again nothing came out. I managed to remove the whole plug and then got to work with some pipe cleaners and wire. This improved things but I got a trickle not a flow. I have been trying to avoid using a chemical flush but I think I will have no choice but to do so. Do you think that would be OK Dieselman, or do you think it could create problems like leaks that were not there before? Cheers…

Possibly, but if rust is the only thing stopping leaks it's best to find that out now.

Try back flushing the drain cock with a hose, to loosen any compacted sludge.

For a chemical flush, white vinegar works, but remember to then flush out with clean water before refilling the system with anti-freeze.