Thirsty V6 Xantia

[addo]

The two letters could just be batch ID codes? Your front strut spheres tally correctly by the part number on them.

[Quackers]

When i had a V6 Xantia i would get 300-350 miles out of a full tank, which was a mix of town and cruising on A roads

[Dommo]

I'd definitely keep the genuine spheres, try and get them regassed, the three dimples on the front corner spheres means they have a better diaphragm than spheres without the dimples, worth keeping and regassing if they need it in my opinion!

[Mandrake]

Although those front strut spheres with the 3 dimples will be the multilayer long life type they still don't last forever, so if they really are the originals on the car (circa 1998) that makes them 13-14 years old. The long life spheres can often last 10 years or so without losing much pressure but after that they they can start to lose pressure, so they're likely to be a bit low on pressure by 13-14.

Citroen also advise against re-gassing the multilayer spheres, from what I understand the reasoning is this - normal spheres lose pressure at a steady and fairly rapid rate (50% loss in about 3-4 years) but as long as they are re-gassed before they get too low their service life can be very long, its only if they're left to get too low in pressure that the diaphragms are damaged.

The long life type go for approximately 10 years with almost no pressure loss but eventually the middle slightly brittle non-porous layer ruptures, leaving only the two outer normal layers, thus their leakage rate dramatically increases to that of a normal sphere losing pressure quickly over a couple of years or so, in addition the ruptured centre layer can cause accelerated wear and rupturing of the outer layers due to the sharp edge of the rupture in the middle layer rubbing against the outer layers with movement.

Long story short is that once the pressure of the long life type sphere has dropped to the normal re-gassing pressure levels where the ride is significantly harder the sphere has already lost its long life low leakage behaviour and is likely to rupture soon, thus isn't worth re-gassing as it will probably fail completely within a year or so...

Does anyone have the sphere tables for the Lizarte spheres so we can check if the rest are the correct type ?

[Mandrake]

Back to the original topic of the thread, I've just got my first accurate MPG figure for the V6, and (as expected) it's quite a bit less than I hoped.

221 miles from 50.1 litres of petrol which works out to 19.8 MPG or 7 km/litre.

About 100 miles of the 221 was single/dual carriageway at 60-70mph, the rest was urban including a lot of short (7-10 minute) journeys to work.

I can understand getting that low a figure if it was all short urban trips, but with nearly half the mileage being motorway I was hoping for better than that...

On my 2 litre I used to get about 23MPG (8km/litre) with purely urban driving, and about 28MPG (9.9km/litre) with mixed urban/motorway.

Is what I got all I can expect from the V6 or is there something wrong ? I haven't been lead footed either, despite the temptation. Does the grade of fuel affect MPG ? I was using 95 unleaded, and I had read that some cars will get lower MPG on lower than optimal grade petrol due to lower efficiency. (In other words the money you save on lower RON number you lose on getting lower MPG and less total running distance)

Another thought is that the front tyre sidewalls look quite badly worn (with some cracking) so despite having the correct pressure in them they always look flat, making me wonder if there is increased rolling resistance due to a weakened sidewall....

Anything else ? Or has the reality of V6 ownership just hit home

[CitroJim]

Anything else ? Or has the reality of V6 ownership just hit home

Nope, that should be better than that. I used to run a V6 as a daily driver and that meant a lot of town work and a short 6 mile each way commute to work. Under those conditions it was more frugal than the Activa. On a run, low 30s are normal if you observe speed limits and don't get too tempted by the sport button. Best I achieved, albeit just after I'd rebuilt the gearbox, taking it very gently on a run was 35.

I reckon you may have hit it with the tyres and tracking Simon and it's also worth checking for binding brakes, both front and rear. Duff tracking can make a huge difference and maybe more on a vehicle that's so weighty at the front...

[CitroJim]

Oh, and running on 98 RON does make a considerable difference to economy, both in the V6 and Activa. They both have knock sensors and can take advantage by allowing the timing to run more advanced...

Seems the premium petrols like BP, Shell and possibly Total give the best results.

[Mandrake]

Nope, that should be better than that. I used to run a V6 as a daily driver and that meant a lot of town work and a short 6 mile each way commute to work. Under those conditions it was more frugal than the Activa. On a run, low 30s are normal if you observe speed limits and don't get too tempted by the sport button. Best I achieved, albeit just after I'd rebuilt the gearbox, taking it very gently on a run was 35.

That's better than I ever got with the 2 litre. Best I think I ever did on long journeys was 32MPG, albeit with 3 people and luggage.

I reckon you may have hit it with the tyres and tracking Simon and it's also worth checking for binding brakes, both front and rear. Duff tracking can make a huge difference and maybe more on a vehicle that's so weighty at the front...

Good suggestion with binding brakes, its actually quite possible. The rear callipers are so badly out of alignment that the disc is practically touching the calliper, and one of the pads was actually rusted solid to the calliper... so even though I've freed up the pads and pistons for now its possible that it is dragging a bit due to the extreme misalignment. The front brakes I haven't inspected at all yet, nor have I checked the handbrake adjustment.

As for tyres, I don't like the look of the front tyres at all, cracked and quite bulgy with scuffing over the entire tread, so there could be extra rolling resistance and possibly wheel misalignment. Hopefully its not due to worn lower arm bushes letting the tracking wander about with load...

A few things to check when I get time to be sure.

[Mandrake]

Oh, and running on 98 RON does make a considerable difference to economy, both in the V6 and Activa. They both have knock sensors and can take advantage by allowing the timing to run more advanced...

Seems the premium petrols like BP, Shell and possibly Total give the best results.

That's what I thought. Unfortunately I just filled up with 95 from ASDA today, so it'll have to wait for next time to try 98 RON.

To get the best out of 98 I should ideally run it down as close to empty as possible, fill up with 98 and then disconnect the battery to force a fast reconfiguration of the ECU for the higher RON ?

Come to think of it the performance does seem to have dropped noticeably over the last 2 tanks of fuel, I wonder if lexi had some 98 in it before ?

[Ratheram]

My 2.0 16v Xantia runs crap on total/bp petrol but I like treating my car to a bit of Tesco Momentum99 petrol. Ok, it isnt shell but it makes it soo much quicker. Doesnt make it more economical, makes my right foot damn heavy though :/.

I dont know if its been covered but, something that often goes overlooked on the petrol xantias... When was the fuel filter last changed?

[CitroJim]

Ahh, supermarket petrol...

There's been a lot of circumstantial evidence to suggest that, despite it meeting all BS requirements, it's not as good on power/economy than that purveyed from the 'premium' retailers like Esso, Shell, BP and Total.

There was a long thread about it a while back.

I never use supermarket petrol but do occasionally chuck a tank of Tesco's finest DERV in Rattiva.

[Ratheram]

BUt I wouldnt touch Total petrol, even if it was 10p a litre less than the others. My car runs terrible on it and its not just the Total garage down the road to my work, its EVERY Total garage! It misfires, hesitates and randomly just cuts out. Thankfully in my huge 8mile drive to work and pack, I pass a Shell garage. All Shell petrol or Tesco 99 petrol, it funs perfect. The others, mhmm, not 100% but works ok

[CitroJim]

That's rather interesting on Total, being it's the stuff Citroen recommend....

Mainly I use BP as that's my nearest garage, just down the road... Esso I use reasonably often and find it OK.

Never tried Tesco 99. Might, on your recommendation, give it a go ion the most sensitive one, the Activa...

Trouble is, our local Tesco forecourt often looks like an imminent tanker driver's strike but then our local Tesco looks like a siege is about to overtake the place. We badly need more Tescos around here...

Or less people...

[Mandrake]

Actually come to think of it the last fill up before today was actually 95 RON from BP, around the time when the tanker strikes were threatened. (ASDA was backed up by 20+ cars that day, and I was nearly empty, but BP was business as usual with no queues) But all my other topups have been 95 from ASDA.

[Ozzie Kuma]

I have just done a 580km trip ( approx 50/50 urban / freeway ) & used 55 liters of 98 with, lets say,the occasional enthusiastic driving ( one can not be gentle with a v6 accelerator , it is just not possible to a normal male!) . It is the first trip since having the steering toes set to 7mm & I believe the car is tracking & running very well , riding & handling like a dream but filling the tank at the end of the day & handing over $100 was a pain. My VSX gets 600k from 55l all urban driving on part ethanol.