Citroen XM Forum

Having read the comments in your screen-grabs reminded me that the owner I acquired the car from told me it was indeed capable of the official V-max, so Shaun isn't the only one to have given the car a good caning.

I know they are. I tried mine once.. but backed off at 140 and she still wanted to go.

Amazing!

All the time I have owned this car I have thought there was some raspy exhaust sound on initial start, but couldn't detect if it was blowing, or not.
I was performing a pre-MOT check and jacked the car up using a beam as a support, when I heard the exhaust note suddenly deepen, so investigated.

The flexi section on the front pipe had broken free for about 90% of it's circumference. This had obviously been cracked previously, but hidden by the worm drive clip holdings recovering braid on.
I welded the crack back onto the collar, but the concertina metal is so thin and had holes in, it was impossible to MIG weld the single thickness pleats.

Here's where the fun started.
I wanted to get the job done quickly and as the pipes into and out of the flexi section are different sizes, rather than ordering some pipe and a flexi, decided to have a new one welded in.

This section of pipe runs from the front manifold to where the pipe humps over the front subframe. The fittings at each end are both angled, have to fit exactly and the length is critical. The manifold connection is a bolted flange, with no adjustment possible, the rear is a ball and socket, but has to fit precisely.

I marked a pair of alignment lines down the exhaust in situ and had the part made (cost...cough, cough, cough )

When I tried to fit the pipe did it fit....





As the pipe had now been altered in length, measuring to get an accurate length was very challenging and required a number of fitting attempts, bolt up to front manifold and mark off, undo and bolt to exhaust and mark off, make allowance for the amount of droop and rotation, etc.
There is literally no margin for error, clearances are only 5mm.

It's one of those jobs you either need to tack the new flexi section in situ, or make a temporary jig to ensure absolute accuracy.

Incidentally, the bulge in the pipe to the left of the flexi section in the first image, is a catalytic converter.
This car was registered less than one month after the requirement to have Cats... There are two larger ones behind the subframe.

Time to get the V6-24v out for an MOT check-over...so of course, it started hailing.

Video
https://go.screenpal.com/watch/cOebjlnZMr0


Of course I had left the door open.
Generally seems good, just needed a battery installing, fitting a wheel-house mud shield and a general check over. I borrowed the mud shield from the Cobalt car that is currently resting.

This car is parked in my garage, but I've noticed an Lhm leak at the front. I put clean cardboard down to monitor if it was just some residual oil, but the card has become wet with Lhm.
I put a battery on the car, turned the starter a few times to prime the oil system, then input the code and fired it up, reversed it to create space and drove it up some ramps.
After a while I noticed the cooling fans come on and thought it was a bit premature, so squeezed the top cooling hose to find it was empty. I stopped the engine and refilled the cooling system with about 4L of coolant, at which point I was somewhat concerned a head gasket might be leaking.

I then went under the car to look at the Lhm leak and found the front Hydractive stiffness regulator was wet with fluid.

On the V6-24, due to routing of the extra exhaust, the front Hydractive stiffness regulator is fitted just behind the cooling radiator instead of under the subframe, behind the engine.

I've not captured it very well, but the complete regulator is wet, with a drip forming on the lower bolt. This indicates the oil is leaking from the sphere fitting, not a pipe union.


I also checked the main pressure regulator, finding it does have some oil on it, only at the base. This could be fluid that has blown back from the Hydractive stiffness regulator, so I wiped it and will re-check at a later date


Having lowered the car, then undone the pressure relief bolt before switching off, I tried to unscrew the Hydractive sphere by hand, which was still tight.
Access is terrible but I managed to fit my tight spaces sphere removal tool and over a considerable time unscrewed it. There was residual pressure locking the sphere screw threads, which there shouldn't have been as I had performed the de-pressurisation procedure correctly.

There isn't sufficient room to withdraw the sphere completely, without removing the distributor cap, rotor arm and possibly the coil and A/c drier.


As the leak appeared to be from the top of the stiffness regulator I simply opted to replace the sphere seal. The old one did appear a little thinner and has some signs of degradation. It's possible I re installed the old seal when first re-commissioning this car and it appears it may have been pinched at some stage, before my ownership. Unless damaged, these seals rarely fail, even if re-used a number of times.


After cleaning the housing and sphere neck, I greased them both, and the seal, fitted it and screwed the sphere back on, ensuring the seal stayed in position. It's not possible to see the seal when fitting the sphere, so I went under the car before final tightening and took an image.
Greasing the sphere flange stops corrosion and reduces friction to the point spheres can readily be unscrewed in future.


As the car was on ramps I decided to look into why the Hydractive sphere hadn't fully depressurised when the system pressure was released. That indicates the electrovalve hadn't remained open long enough for the sphere to empty.

As the car was now fully low, access was poor, additionally the electrovalve cover was bent causing it to be very awkward to remove. There are three 10mm headed bolts to undo, the rear one has a loose nut inside the plate, so a spanner was needed also.


Bent plate.


I parted the electrovalve electrical connector, finding it appeared clean, but cleaned with contact cleaner and greased it before refitting.
I checked the electrovalve was functioning by opening and closing a door, then feeling and listening to the electrovalve until it switched off with a healthy clunk.
I then refitted the metal plate, which I had cleaned and re-formed appropriately.

I ran the engine again and quickly noticed coolant dripping off the belt end of it.

I switched off to investigate and saw coolant running out of the water pump weep hole, which in context, is good news.


The front of car was up on ramps, with the rear sticking out of the garage. I needed to run the engine to check the suspension was working properly, which appeared to be fine, but then it did what V6-24 do best...ran out of petrol...
I had about 1 litre in a can, which was just enough to get it going again and off the ramps.