I have a Xantia S2 V6

[bxzx16v]

Impressive mpg results Mike from the V6 , I had a Renault 25 V6 turbo (manual) years ago and that what pretty decent on fuel for what it was , on the motorway it would crack nearly 40mpg if driven correctly .

Mark

[Northern_Mike]

Yes, I was surprised myself. My route to work isn't particularly town driving, mostly 30/40/60 zones, but there is traffic and it usually takes me about 35 mins to do 20 miles. Some very slow bits as there are often horses and cyclists, and occasionally dullards just going too slow which requires a good prod to get past safely..

[bxzx16v]

I'd really love a V6 Xantia oneday .

Mark

[Northern_Mike]

They're great tools.

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[bxzx16v]

I would be tempted but the Zx has been 100% reliable in the 3 1/2 yrs I've had it and the laguna is just an amazing allrounder. I may have to part with one of them soon, which one I'm not sure as they both have their merits. If I did part with the Zx I'd never be able to replace it with another with the pedigree it's got as they are so rare. Even though it only gets used during the summer it's just great fun.

Mark

[Northern_Mike]

Impressive mpg results Mike from the V6 ,

Yes. Here's the full stats. I ran it dry, I put £15 in it at 1.29/l and had done 74 miles when I got to work this morning. The needle was at the bottom, or near enough. I did say I wasn't going to let it run dry, but as I had a fuel can with about a fivers worth in the boot, I thought I'd dare it to run out on me on my journey home.

It's now showing 93.7 miles and hasn't ran out.

I thought I felt it stutter coming through Windsor so I gave it the beans up a hill near Fifield expecting it to stutter more but no. I got home.

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[Northern_Mike]

Oh, and of course, today we had the first problem When starting from cold, STOP light stayed on with the red light in the temp gauge. Went off after about 200 of setting off, never to show itself again until the next cold start 12 hours later.

It's lashing down so I haven't actually checked any levels, but I know the LHM is ok.

ideas?

[lexi]

water level.

[Northern_Mike]

water level.

Yeah, header tank is bone dry.Now topped up. Ruined it for me though.

[Northern_Mike]

Speaking to the experts, it appears most V6 Xantias use a bit of water and need topping up often. That's made me feel better.

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[Mandrake]

A genuine 32.2mpg off my calculations. It might be a tiny bit more, but I'm not prepared to run it any lower this time. It did run dry on me, I put fuel in, and the needle is now on the bottom, not even rising from the stopper. The fuel used works out at 32.2mpg if it were dry *now*, which it isn't.. So, I'm quite impressed with that as while I have not been teararsing about, I've not been driving in a fuel saving mode either. It's better than I ever got out of an Activa, apart from one 65mph cruise ip the motorway.

This mileage was brought to you by BP standard 95 RON cheapo petrol at 128.9p per litre. It'll be getting Sainsbury's stuff next, as the petrol station is by the office.

Mike, that's closely in line with what I've seen - on the 800 mile trip around Scotland I did in 2012 with four passengers and a boot full of luggage I averaged 32.8MPG across the whole trip.

That was running on 95 RON from various small name petrol stations, I wasn't driving like a maniac either but nor was I driving for economy. If there was a truck that needed passing I was booting it, and I was crusing at 70mph a lot of the time.

Of course that was back before all the engine performance problems, so I have no idea what it would manage at the moment on a long trip.

[Mandrake]

Speaking to the experts, it appears most V6 Xantias use a bit of water and need topping up often. That's made me feel better.

Only if your coolant expansion chamber is leaky, which they probably all are at this age unless they've been replaced... They develop a pressure leak where the seam is half way down the tank. They only leak under full working pressure so when the car is parked no leak is in evidence. I once caught mine red handed after a hard motorway trip where I stopped and popped the bonnet immediately and there was a fine spray of mist coming out of the seam on the side of the bottle.

Mine was loosing enough coolant that the warning would come on every 6 weeks or so and need topping up. As a workaround I started running it with the pressure cap loose and it stopped using coolant - none used at all in months.

In the last month I finally got off my backside and changed the coolant expansion chamber - a brand new one from Citroen is only £40 inc VAT and takes maybe 20 minutes to change. I changed mine while the inlet manifold was out doing another job which made access a lot easier but it should be possible without removing the manifold. There's only two hoses, a wire for the level sensor and two nuts. Draining the whole system is not necessary, I just syphoned as much as I could out of the bottle before disconnecting the bottom hose.

Since replacing it I'm running with the pressure cap tight again and so far, touch wood, no coolant loss.

[Mandrake]

Good to know Simon. Did you replace with a new or reclaimed chamber? Wondering if these are still available off the shelf?

Brand new, as I said above. Glasgow Citroen didn't stock them on site (hardly surprising) but ordered it up from Citroen UK in two days.

It doesn't come with a pressure cap, level sensor or rubber blanking plug for the front - the level sensor and blanking plug I just transferred from the old one and I bought a new cap (also available for about £8) just for peace of mind in case mine was somehow seized causing excessive pressure build up. (Unlikely, the old one looks fine)

A new level sensor is also still available but costs more than the entire expansion chamber! (a bit cheeky, considering its just a small piece of plastic with two metal prongs)

[Northern_Mike]

I spoke to Jim about it, he reckoned even without the leaky header tank, it's not unknown for them to use a bit of water. Both of his do, only a little. One way to find out - I'll pressure test it on Monday. I have instructions on how to build a pressure tester from a friend who built his own for his MK4 Golf to work out where it was leaking from a couple of months ago, using no more than a piece of old bike innertube with the valve, and a couple of bits of pipe. I can already see where I could attach similar to the header tank. If it's cracked, it'll show when I pressurise it cold won't it?

[Mandrake]

I spoke to Jim about it, he reckoned even without the leaky header tank, it's not unknown for them to use a bit of water. Both of his do, only a little.

That's as may be, but you still have to wonder where the water went...you would think if there is even a small loss it must be going somewhere, whether through a leaky head gasket, heater matrix etc...

The only other thing I can think of to explain water loss without a leak is if the expansion vessel has been designed to be too small for the amount of coolant in the system - when the system heats up and the water expands the expansion vessel fills up and blows of excess coolant through the pressure cap relief port at the rear, then when it cools down again it contracts low enough to set off the low level alert... a bit like a combi-boiler with an expansion vessel that is low on gas pressure which will keep losing water through the pressure relief valve.

Another month or two and we'll see at what rate I'm loosing coolant (if any) with my new expansion vessel. If it stops completely then its a fair bet that the expansion vessel was to blame. Apparently the de-gasser sphere can leak too but I thought I'd replace one thing at a time as the de-gasser sphere looks a lot harder to replace and I already knew for sure the expansion vessel leaks. (Coolant stains from the seam kind of give the game away )

One way to find out - I'll pressure test it on Monday. I have instructions on how to build a pressure tester from a friend who built his own for his MK4 Golf to work out where it was leaking from a couple of months ago, using no more than a piece of old bike innertube with the valve, and a couple of bits of pipe. I can already see where I could attach similar to the header tank. If it's cracked, it'll show when I pressurise it cold won't it?

No idea - I've never tried a test like that. The new pressure cap came with a pressure figure on it, I can't recall for sure what it was, but I think it was 1.4 bars. The blanked off spigot on the front right side of the expansion vessel looks like the ideal place to attach a pressure testing apparatus...