Xantia V6 in France...

[CitroJim]

That car is destined to remain the best S1 V6 in the world and no doubt end up in a museum one day

[xantia_v6]

I got both cars out of the garage last week, the XM still operating perfectly (a flat battery the next day turned out to be caused by a USB power adapter plugged into the light socket).
The Xantia is also running fine, but still has a few little niggling issues to sort out.

The A/C mostly works well, but has a couple of quirks. The first is that the blower only blows at full speed in the manual speed position, in Auto mode, it blows fast-ish, but not at full speed, even when the temperature in the car is over 30 degrees and the temperature control is set of full cooling. I am sure that previous Xantias would blow at full speed in Auto mode. Can someone confirm this? It is a 1997 Mk1.

The other quirk is that on a hot day (over 30 degrees external and hot sun), the A/C works well for about 20 minutes driving, until the interior gets down to the set temperature, and the blower speed drops, then the A/C goes into a mode where the blower shuts off completely for about a minute, before coming back on. I have a theory that the system may have been slightly over-filled, and the high pressure cut-out switch is causing this, but have not been able to catch the behaviour when I have a meter in my hand or Lexia connected.

[Stickyfinger]

My blower only works to about 3/4 fan speed on Auto

[CitroJim]

Good to hear all is good with the cars bar the A/C issues Mike...

Alasdair, I'll have a chat with you about yours...

[Stickyfinger]

ohh, I thought that was standard ?

[Mandrake]

The A/C mostly works well, but has a couple of quirks. The first is that the blower only blows at full speed in the manual speed position, in Auto mode, it blows fast-ish, but not at full speed, even when the temperature in the car is over 30 degrees and the temperature control is set of full cooling. I am sure that previous Xantias would blow at full speed in Auto mode. Can someone confirm this? It is a 1997 Mk1.

Like Stickyfinger's my 1997 S1 V6 has never blown the fan at full speed in auto mode, regardless of temperature differentials between measured and set temperature. 3/4 maximum speed at most in Auto. The auto fan speed is usually less than I would like it to be so I often use it in manual mode.

However on my old NZ 1997 S1 2.0i the auto mode definitely did blow at full speed when the interior of the car was a lot hotter than the set temperature when first getting into the car! The behaviour of the climate control in particular fan speed in auto seems very different between the two cars.

The climate control logic including auto fan speed changed quite a bit between S1 and S2, but like a lot of other things (cruise control) it did not seem to change exactly on the S1/S2 transition.

The other quirk is that on a hot day (over 30 degrees external and hot sun), the A/C works well for about 20 minutes driving, until the interior gets down to the set temperature, and the blower speed drops, then the A/C goes into a mode where the blower shuts off completely for about a minute, before coming back on. I have a theory that the system may have been slightly over-filled, and the high pressure cut-out switch is causing this, but have not been able to catch the behaviour when I have a meter in my hand or Lexia connected.

The high pressure cutout switch for the AC would only stop the compressor - it would not cause the cabin blower fan to stop.

More likely the problem is the other way around - the blower fan is stopping due to some other fault and because the fan stops blowing air through the evaporator it will trigger either the anti-frost sensor on the evaporator or the high pressure limit switch on the dryer bottle, or both!

When this happens does the blower fan remain completely stopped in auto if you turn off the AC switch ? If so the problem is not related to the AC... Also can you get the fan going again in the manual speed position ? I'd start by checking the the connector on the blower itself - I had a lot of trouble with that connector overheating on my NZ Xantia, in addition to the ignition switch issue. I assume you've already done the ignition switch blower fan modification ?

[Zelandeth]

If the system is overcharged and going out on the high pressure switch I'd expect to see a behaviour where the compressor would drop out and the engine fans would be on full speed (to try to bring the condenser temperature down). I'd not generally expect it to interact with the interior fan...though I don't know the specific quirks of the firmware...happy to fool mine into thinking the HP switch has triggered to find out what it does if it would be helpful.

If it's overcharged one behaviour you might also see is rapid icing of the evaporator...if there is hardware in place to detect that, that may see the interior fan stopped. I'm assuming there's no specific defrost mode and it will just shut everything down and "wait for it to thaw" rather than faffing about with a hot gas defrost or heater element etc...

Mine on auto actually runs the interior fan a lot faster than I'd like generally if set to auto because of the noise levels, and definitely will run it at full speed if the car is far hotter (or colder) than the setpoint.

Really wish I still had my HVAC gauge set...

[xantia_v6]

I will make a more accurate description of the symptoms next time we have a hot day.

[Mandrake]

If the system is overcharged and going out on the high pressure switch I'd expect to see a behaviour where the compressor would drop out and the engine fans would be on full speed (to try to bring the condenser temperature down). I'd not generally expect it to interact with the interior fan...though I don't know the specific quirks of the firmware...happy to fool mine into thinking the HP switch has triggered to find out what it does if it would be helpful.

The high pressure switch will indeed put the radiator fans onto full speed. It doesn't stop the cabin fan though - that would be counter-productive as it would cause the evaporator to ice up. In fact under normal circumstances when you set the fan speed to off it always turns the compressor off as well. So I see no reason why it would want to stop the cabin fan when there is risk of icing.

If it's overcharged one behaviour you might also see is rapid icing of the evaporator...if there is hardware in place to detect that, that may see the interior fan stopped. I'm assuming there's no specific defrost mode and it will just shut everything down and "wait for it to thaw" rather than faffing about with a hot gas defrost or heater element etc...

If you put a Lexia on the car you'll see there is a temperature sensor on the evaporator - on my Xantia it typically reads about 2-4C when the AC is on and if it goes below about 2C (for example the fan is set really low) it cycles the compressor off to stop it icing.

I would have thought a temperature sensor on the evaporator that can shut off the compressor was mandatory to avoid icing the evaporator ?

[xantia_v6]

The Xantia has not had anything to write about this year, it has been driven to the supermarket a few times and once to Chalons-sur-Saone, probably totalling about 100 km for the summer.

Last week, the front suspension did not feel right when cornering, and a bounce test today confirmed a failed sphere, and it certainly has a ruptured diaphragm. I have fitted a spare that I had from an XM, and the ride feels good again.

When I got the car in 2016 both front spheres were replaced with genuine new old-stock spheres (of unknown age) which were pressure checked, and found to be on specification. One of these failed, I think in 2017, and the second now. It goes to show that regardless of the lack of leakage, the diaphragms of NOS spheres are not to be trusted.