Citroen XM Forum

Hi,

I need an expansion tank for my N reg XM 2.5TD.
Part number is 1307GA

Anyone got one tucked away, or anyone breaking a 2.5?

Thanks
Rebecca

These seem to be failing and getting rare to find as this is the fourth request I have seen in the last two months.
Quite a few I have examined had either a split central joint or the internal red baffle system had broken up.

John

Mounting of these expansion bottles directly in engine bay locations doesnt seem to help them. The xantia v6 also had the same issue with its expansion bottle mounted at the back of the bay to the right of the inlet manifold...

I dont recall many issues with bottles mounted on the drivers s

ha - well mine failed on the seam and the baffle broke up. I managed to fish out the remains of the baffle when I took it out to 'repair' it.

I think the best option is going to be to get one of the car mod specialists to make one up to fit.
If they're making one - is it worth making a few up? If others are having the same issue... better a ~£100 tank than a scrap XM

Rebecca

Hi Rebecca

I cut one with a failed baffle up last week to to see the internal construction.
It was clear that the centre red section was originally a very complex plastic casting.
Both of the two black half spheres had a number of position slots for the centre section.
There was just not enough physical bits left to work out the actual centre shapes.
Not willing to cut up a good recovered one to find out.

I think I will have enough spares for my own long term needs.
As with a few other unique 2.5 bits they are items I no longer supply on to others.
I doubt there would be much take up of made up ones at the price you suggested.
Most people have little interest in such projects until actual need happens.

The UK has been checked out for any NOS.
This from an Indy chasing for one for a customer.

France is more likely to be a source.
It may be worth contacting Frederick who is good at supplying XM bits to members on here.

John

I might also need one. A slow consumption of water, no other obvious signs and suspicious hissing sound from that area with a hot engine. But no visible traces of water. Not yet decided but the tank just could be it. I haven't checked the local sources yet.

Hi Gabor

Common for lost coolant to evaporate off a hot tank leaving very little sign.
Leaking centre join is covered by the metal band.
Check out the level stat first as on these one of the two locating lugs can break off causing leaking.

John

What's that level stat to look for? The sensor maybe? Nothing suspicious there so far but I'll have another look.

By the way, the first idea was the cap, already replaced and now even running on two rubber gaskets (the new and an older, already thinner one) because the new one itself wasn't convincingly tight.

The level sensor 'seal' relies on an O-ring, which can be renewed. As John says, the bayonet-action lugs are somewhat delicate.
Many coolants leave a white-blue dry trace behind where there's been a leak. Plain water won't do this.
The OE pressure-cap's rubber washer is quickly damaged by any oil-in-water; it goes soft and swells, giving a poor seal.

Over-filling the header tank can result in repeated coolant loss.
Owner's handbook iirc refers to the correct level being c.20mm above the red vertical marker. If filled to this level, the engine will repeatedly expel coolant, I find. If filled to c.20mm below the top of the marker, the level stays there indefinitely.

I am intrigued by the reported complexity of the tank's internals (although I've never split one open to examine).
It is described as a de-aeration chamber - which makes sense - and obviously performs an expansion and header function.
It doesn't seem, at first sight, to operate on the swirl-chamber principle that some other PSA cooling systems do, but I'm not sure what the (red) internals actually do. I wonder whether a simple tank might suffice, with top entry and lower exit piping in similar positions. Unsure whether the unit has to cope with a high fluid throughput or not.