New Member, New C5, Some Little Issues!

[Guest Dan Slatford]

Hello all,

 

I took the plunge last week and upgraded my Xantia for a C5. 2001 model, 2.2HDi, overall great condition and (mostly if not all) dealer serviced, ex fleet. 105k (but might be more! read on). The first thing I did was have a new cambelt + full kit, water pump, pulley and aux belt fitted.

 

It seems to run fine (touch wood, after having read many posts here!) but there's some issues. Firstly after my 400 mile round trip this weekend, it's obvious that the odometer is under-reporting the mileage. It's out by about 0.1 miles / 3 miles, or around 7.5 miles / 200 as I first noticed on Friday. (The time-trial on the A42 northbound is exactly 3 miles in my previous Xantias, but 2.9 in this!)

 

I believe the wheels are of the correct size (R15), so other than wheel diameter, what could be causing this? I wasn't aware that anything could really go wrong with the odometer calibration... probably unrelated, but there's also a slight pull to the left and steering wheel vibration over ~ 60, presumably just tracking/balance, but not sure if this can really affect mileage readout.

 

Less important, it reckons it's 60 deg C outside! (definitely centigrade). I'm hoping this might be why with the climate control on auto, it insists on having aircon on all the time, and unless I turn it up to max 28deg C, the temp doesn't really change from 'mild'. Am I right in thinking the outside thermistor is the little nipple under the nearside wing mirror, if so, is this an easy replacement, assuming there lies the fault?

 

Oh yes, and something about the front suspension squeaks - best way to describe it is a small bird cheeping on bouncing the offside corner!

 

There's a couple of other bits, drivers door rarely unlocks with central locking, and nearside front window tends to get stuck when wound down, but I'm sure I'll solve those after some investigation. So far it's a stunning car, most luxurious ride I've ever had - and (allegedly) some 45.6mpg from Bristol > Leeds!

[Johndouglas]

Having now got a C5, but have had a 2.1 Xantia in the past, I would say that the C5 speedo/odometer is more correct than the Xant. I always took the Xantia to be about 5% over whereas the C5 almost agrees with satnav and mileage agrees with Microsoft autoroute.

 

And yes, the outside temperature is read from the nipple on the nearside mirror. The nipple is replaceable after removing the mirrow.

[Guest Dan Slatford]

Having now got a C5, but have had a 2.1 Xantia in the past, I would say that the C5 speedo/odometer is more correct than the Xant. I always took the Xantia to be about 5% over whereas the C5 almost agrees with satnav and mileage agrees with Microsoft autoroute.

 

You may be right. I've just checked the same route on Multimap, and it's 193.5 miles - exactly what the C5 claims! My previous three Xantias (and I think, the old clockwork Sierra) all read 200. I'm amazed!

 

Just ordered a temperature sensor too. ~£20 is a bit steep for what's probably just a thermistor costing pennies, but I suppose it's a small cost to put the climate control right.

 

I wonder about this squeek from the suspension though. The Xantia's front struts sometimes did that when the LHM was old/dirty, and new blood cured it. I've no idea if the LDS has ever been changed so that could be the culprit (it really sounds like there's a birds nest somewhere under the bonnet while driving slowly!) Some people I see have asked before, but I can't find any guide to flushing C5 LDS. Is there a useful post I've missed anywhere, I wonder? No idea what the procedure is on these cars. I'm not even sure right now where the LDS tank is!

[Alzee]

You may be right. I've just checked the same route on Multimap, and it's 193.5 miles - exactly what the C5 claims! My previous three Xantias (and I think, the old clockwork Sierra) all read 200. I'm amazed!

 

Just ordered a temperature sensor too. ~£20 is a bit steep for what's probably just a thermistor costing pennies, but I suppose it's a small cost to put the climate control right.

 

I wonder about this squeek from the suspension though. The Xantia's front struts sometimes did that when the LHM was old/dirty, and new blood cured it. I've no idea if the LDS has ever been changed so that could be the culprit (it really sounds like there's a birds nest somewhere under the bonnet while driving slowly!) Some people I see have asked before, but I can't find any guide to flushing C5 LDS. Is there a useful post I've missed anywhere, I wonder? No idea what the procedure is on these cars. I'm not even sure right now where the LDS tank is!

 

 

Dan, where have you ordered the temp sensor from, if you dont mind me asking?

 

I believe this could also be the cause of my cabin temperature not warming up for ages mornings. With the heating control ramped all the way up, it still takes about 30mins to get any degree of comfort on cold Scottish winter mornings. Brrrr

[Guest Dan Slatford]

Dan, where have you ordered the temp sensor from, if you dont mind me asking?

 

From a Citroen dealership (I think they all have a parts counter?)

 

I'll fit it tomorrow after I pick it up. My heater only blows hot if I turn it up to 28 (I have dual climate, don't know if other systems have or use the outside sensor), cold on 17, but the same "coolish" temperature anywhere else.

 

I hope with this fitted I can leave it on auto without the aircon jamming on!

[800jimbo]

It seems to run fine (touch wood, after having read many posts here!) but there's some issues. Firstly after my 400 mile round trip this weekend, it's obvious that the odometer is under-reporting the mileage. It's out by about 0.1 miles / 3 miles, or around 7.5 miles / 200 as I first noticed on Friday. (The time-trial on the A42 northbound is exactly 3 miles in my previous Xantias, but 2.9 in this!)

My C5 is under reading. Every time I pass a Gatso I am going slightly faster than everyone else.

 

I used my old Tomtom today to check the GPS speed - at a speedo reading of 80 the Tomtom had me at 83-84 ish. Whilst the Tomtom isn't necessarily spot on it has in the past read at around 77-79mph in two other cars (same stretch of road) where each car's speedo was showing 80.

 

So the C5 seems to be reading about 5 or 6 mph less than my other cars at 80.

[seefive]

From a Citroen dealership (I think they all have a parts counter?)

 

I'll fit it tomorrow after I pick it up. My heater only blows hot if I turn it up to 28 (I have dual climate, don't know if other systems have or use the outside sensor), cold on 17, but the same "coolish" temperature anywhere else.

 

I hope with this fitted I can leave it on auto without the aircon jamming on!

 

 

Hi

I don't believe the external temperature sensor affects the climate control. My temp display went crazy last summer - gave me an ice warning on a warm May afternoon, but the cabin remained cool, as it should do. On a cold morning, my 2002 sx petrol is warm within 2 minutes, then the blower slows down and remains tepid to maintain the internal temprature. I leave the temp on 19 (my side) and 20 on the passenger side all year round, and it's always comfortable.

There must be an internal sensor that looks after the cabin tempearture. Interested to know where that is...

[Guest Dan Slatford]

There must be an internal sensor that looks after the cabin tempearture. Interested to know where that is...

 

Well, I've replaced the external temp sensor now (that mirror was awkward to dismantle!) and the climate controls work fine - whereas before anything between 16 and 28 would give the same temperature air, now the outside temp can be read I can adjust the inside temperature to anything I want.

 

Mine has dual climate control, and the internal cabin sensor must be the little grille beneath the LCD display, between the buttons. The Xantia had a tiny fan to suck air in and past its internal sensor, I presume this may do the same. When I once dismantled a Xantia MKII dash though, there were temp sensors all over the place inside!

 

The aircon insists on being on whenever I have auto switched on though. This is rather annoying, I don't want to wear out my compressor or loose any mpg on needless air conditioning. Reading a few other posts, this appears to be normal behavior :rolleyes:

[myglaren]

The aircon insists on being on whenever I have auto switched on though. This is rather annoying, I don't want to wear out my compressor or loose any mpg on needless air conditioning. Reading a few other posts, this appears to be normal behavior :rolleyes:

 

Hit the 'Economy' button that turns the aircon off and just relies on cold air coming in to moderate the temperature.

[Guest Dan Slatford]

Hit the 'Economy' button that turns the aircon off and just relies on cold air coming in to moderate the temperature.

 

There is no Economy button. I gather some C5s (I imagine depending in which part of the world they're sold) have an economy button to turn the aircon *off*, while others - such as mine - have an aircon button to switch it *on*. If I hit the aircon button to turn it off, it switches off auto mode with it.

 

Although as I discovered today if the outside temp hits 3 or 4 deg C, it doesn't turn on in auto. Still seems pretty daft to me to have the aircon on much at all, if the outside temp is several degrees below the cabin temp.

 

Although frankly I can't see myself keeping auto on very much. It also insists on having air blowing through the top and bottom vents only. I prefer to feel a mild draft from the central vents!

[myglaren]

Although as I discovered today if the outside temp hits 3 or 4 deg C, it doesn't turn on in auto. Still seems pretty daft to me to have the aircon on much at all, if the outside temp is several degrees below the cabin temp.

 

It reduces condensation while the car warms up, you can set it on recycle and it warms up even faster without the windows fogging up.

Bugger about the aircon controls, I had incorrectly assumed that they were all the same.

[72dudes]

It reduces condensation while the car warms up, you can set it on recycle and it warms up even faster without the windows fogging up.

Bugger about the aircon controls, I had incorrectly assumed that they were all the same.

 

No, I think you are right. Dan, hit the aircon button to turn it off (green indicator light should go out, then adjust direction, airflow speed etc to your preference.

 

If you want "auto" with aircon "off", first hit auto button so green light comes on (aircon green light button will also come on) then hit aircon button so green light goes off. Auto button may stay on or go off depending on what the system senses. It should work well, if not you may have another problem.

[Randombloke]

If you want "auto" with aircon "off", first hit auto button so green light comes on (aircon green light button will also come on) then hit aircon button so green light goes off. Auto button may stay on or go off depending on what the system senses. It should work well, if not you may have another problem.

 

I do exactly this and mine works very well. Having turned the air con off the heat, auto vent selector and auto fan control still do the biz.

 

I have also, as mentioned here by Dan, seen the auto be on but the compressor/air con turned off below about 4C.

 

I suspect that there is a humidity detector. I do like the rapid demist and the fact that the C5 doesn't mist up in auto mode.

[Guest Dan Slatford]

I do exactly this and mine works very well. Having turned the air con off the heat, auto vent selector and auto fan control still do the biz.

 

When you switch aircon off, how do you know vent selector and fan speed are still on auto - is the auto button's green light still on? Mine goes out if I try to over-rule any decision, which leads to to believe true climate control is therefore disabled. I'm not really that bothered, but if true, seems a stupid design.

 

On another note, I'm beginning to suspect my new C5 is also returning abnormally low mpg :angry: The slightest incline and the computed mpg drops to mid-20s or even less. It seems to drink fuel as soon as the turbo cuts in, and does feel a little sluggish most often (but then my only frame of reference is a 1.9TD xantia). Except weirdly, a couple of times it's felt like a whole different beast, and pulling out of junctions has thrown me back in my chair with unexpected explosion of power! I wonder if there's a turbo leak anywhere, the turbo is rather noisy - from inside sounds pretty much like a HVG going uphill! I quite liked that, but maybe it's not normal..?

 

It looks like there's been some oil seeping (or maybe blasting) out of the turbo pipes just underneath the plastic engine cover. Doesn't look very fresh, maybe a fault that's already been fixed, but could be a clue.

[Randombloke]

When you switch aircon off, how do you know vent selector and fan speed are still on auto - is the auto button's green light still on? Mine goes out if I try to over-rule any decision, which leads to to believe true climate control is therefore disabled.

 

When I turn the compressor off for the air con, the auto green light goes out but the fan speed still changes by itself, usually if I change the temperature demanded. I'll double check this when I next drive it.

 

 

I wonder if there's a turbo leak anywhere, the turbo is rather noisy - from inside sounds pretty much like a HGV going uphill! I quite liked that, but maybe it's not normal..?

 

It looks like there's been some oil seeping (or maybe blasting) out of the turbo pipes just underneath the plastic engine cover. Doesn't look very fresh, maybe a fault that's already been fixed, but could be a clue.

 

Check for turbo leaks and also check the the air mass flow sensor and manifold absolute pressure sensor wires are properly connected and secured. Failing that, simply check all wires to sensors are properly on. Might also be worth checking that the clip that takes up the slack in the throttle is not loose......

[Guest Dan Slatford]

Check for turbo leaks and also check the the air mass flow sensor and manifold absolute pressure sensor wires are properly connected and secured. Failing that, simply check all wires to sensors are properly on. Might also be worth checking that the clip that takes up the slack in the throttle is not loose......

 

This weekend I'll give the oily bits a good clean up and check everything else. I've been doing a little research (how I wish there was a Haynes manual, however crap they've become!) and really amazed at the complexity of these engines.

 

The two oily pipes appear to be the hot and cold butterfly valves, which seems part of the intercooler bypass system, presumably used when the DPF is going through a regen cycle. I've had a listen for obvious leaks, but nothing near the front pipes as far as I can tell. From inside the turbo does sound more like an intense rushing of air than a typical whistle, but with the bonnet up, revving to 3k, only sounds like it's from the turbo itself (or in that vicinity). If there is a leak I don't think I can diagnose it myself.

 

But the MPG drops through the floor whenever I hear the turbo work. It can drop to 20 or below just going up a slight incline. Cruising on flat around 65-70 returns maybe 44, once the engines warmed up, but any acceleration and turbo-noise even on flat and it drops to low 30s. Can't be right...

 

There's plenty of slack on the throttle (although I don't know where this clip is you mention). Which is the air mass flow sensor - is that the sensor just after the air filter? And MAP sensor, no idea where that is yet!

[Randombloke]

On another note, I'm beginning to suspect my new C5 is also returning abnormally low mpg :( The slightest incline and the computed mpg drops to mid-20s or even less.

 

Check that the brakes are not binding. This is a problem with some C5s. I got my checked immediately after purchase.

 

You can check this easily by raising the car to maximum height then it's just 2 turns on the jack at each wheel.