Coolant warning light on with ignition - off when started
Moderator: RichardW
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
Coolant warning light on with ignition - off when started
Is it normal for the light to come with the ignition and extinguish on engine start? The Citroen handbook doesn't mention it though it tells me how all other lights should act/react so I find it a little puzzling.
It hasn't bothered me before but today I got the warning light while driving and found I needed to top up the coolant with about 400ml - indicating a small leak somewhere.
What's the best DIY method to detect coolant leaks? I can see/smell no clues other than a slight green furring along the top fins of the radiator but no indication of water or steam coming from it.
It hasn't bothered me before but today I got the warning light while driving and found I needed to top up the coolant with about 400ml - indicating a small leak somewhere.
What's the best DIY method to detect coolant leaks? I can see/smell no clues other than a slight green furring along the top fins of the radiator but no indication of water or steam coming from it.
-
- Moderating Team
- Posts: 11563
- Joined: 02 Apr 2005, 16:11
- Location: Charmouth,Dorset
- My Cars: Currently:
C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red
In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars. - x 1199
This will happen if the water level is low as the water contracts as it cools and then expands again when heated, hence the level rises and puts the light out, a rise in water level can also be caused by a leaking head gasket as the pressure build up tends to push the water out of the block, check around the header tank cap and overflow for signs of coolant being blown out, this would show up as white streaks. Green furring would indicate a leak of coolant, but again it may only be happening when its cold, the expansion when hot closing the gap.
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
Hi Peter, sorry if I didn't make myself clear.
Whether the coolant is stone cold, warm or hot, the warning light will illuminate on ignition and immediately go out on engine start, in fact I think it goes out when cranking.
Even so, this is a temperature warning (top part of the coolant temp gauge), not a level indicator isn't it? I don't understand how a low level can cause a (too) high temperature reading.
I'll look for white streaks around the expansion bottle - you've given me an idea I'll install a catch bottle to the overflow as well.
Can you please clarify your point about green furring and coolant leaking only happening when cold and the gap closing? I understand water expands when hot but what gap are you referring to that gets closed when hot?
Thanks
Whether the coolant is stone cold, warm or hot, the warning light will illuminate on ignition and immediately go out on engine start, in fact I think it goes out when cranking.
Even so, this is a temperature warning (top part of the coolant temp gauge), not a level indicator isn't it? I don't understand how a low level can cause a (too) high temperature reading.
I'll look for white streaks around the expansion bottle - you've given me an idea I'll install a catch bottle to the overflow as well.
Can you please clarify your point about green furring and coolant leaking only happening when cold and the gap closing? I understand water expands when hot but what gap are you referring to that gets closed when hot?
Thanks
I expect the light is wired in with the oil pressure warning light - and separated from it by a diode. The idea is that the bulbs are tested when the ignition is turned on but as soon as the engine is running its extinguished - at the same time as the oil pressure light goes out.
There may be others similarly wired (can't think of any at the moment)
There may be others similarly wired (can't think of any at the moment)
jeremy
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
Ah right, thanks for that Jermey, the Haynes wiring diagrams confuse the hell out of me. I wanted to know what circuits were linked to what as I have so many electrical faults.
All I know is the guages are fed from a voltage stabiliser in the dashboard circuitry and the sensors provide a variable resistance to earth. While both my temp and fuel gauges appear to be working I'm not sure about their accuracy as the fuel gauge seems to be indecisive and overly pessimistic.
What I did notice was that the temp gauge remained in the normal zone (above 70 below 90) when the warning light came on during driving.
All I know is the guages are fed from a voltage stabiliser in the dashboard circuitry and the sensors provide a variable resistance to earth. While both my temp and fuel gauges appear to be working I'm not sure about their accuracy as the fuel gauge seems to be indecisive and overly pessimistic.
What I did notice was that the temp gauge remained in the normal zone (above 70 below 90) when the warning light came on during driving.
-
- Moderating Team
- Posts: 11563
- Joined: 02 Apr 2005, 16:11
- Location: Charmouth,Dorset
- My Cars: Currently:
C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red
In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars. - x 1199
Hi Mike
OK sorry about the confusion. Regarding the leak I was only suggesting that a leak from a metal construction i.e. the radiator, can leak when cold but natural expansion could cause the gap to close when hot. The best time to look for leaks is soon after starting, while the water temperature is rising and the pressure building but the system still cold.
OK sorry about the confusion. Regarding the leak I was only suggesting that a leak from a metal construction i.e. the radiator, can leak when cold but natural expansion could cause the gap to close when hot. The best time to look for leaks is soon after starting, while the water temperature is rising and the pressure building but the system still cold.
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
No, no apology needed, I'm sorry for being thick! I get like this sometimes - other times I'm fully asleepPeter.N. wrote:Hi Mike
OK sorry about the confusion.
Thanks for spelling it out for me Peter and that's a good tip I'll try tomorrow.Peter.N. wrote:Regarding the leak I was only suggesting that a leak from a metal construction i.e. the radiator, can leak when cold but natural expansion could cause the gap to close when hot. The best time to look for leaks is soon after starting, while the water temperature is rising and the pressure building but the system still cold.
- xantia_v6
- Forum Admin Team
- Posts: 9052
- Joined: 09 Nov 2005, 22:03
- Location: France or NewZealand
- Lexia Available: Yes
- My Cars: -
1997 Citroen Xantia V6 (France)
1999 Citroen XM V6 ES9 (France)
2011 Peugeot 308 CC THP 155 (NZ)
1975 Jaguar XJ-S pre-HE (NZ) - x 825
hints:
1. I think that on a Xantia with A/C, the coolant warning light is driven from the bitron unit, which has a separate temperature sensor from the guage, and this sensor (or the connection to it) can become intermitent.
2. It seems that a common "invisible" water leak is the water pump seal, a reason for changing the water pump every time the cambelt is changed.
3. By far the best way to detect a coolant leak is to presurise the system while it is cold. You may be able to do this with a bicycle pump connected to a bleed valve. (have not tried it on a Citroen), but NEVER presurise above the rated system pressure or you will blow a seam on the radiator.
1. I think that on a Xantia with A/C, the coolant warning light is driven from the bitron unit, which has a separate temperature sensor from the guage, and this sensor (or the connection to it) can become intermitent.
2. It seems that a common "invisible" water leak is the water pump seal, a reason for changing the water pump every time the cambelt is changed.
3. By far the best way to detect a coolant leak is to presurise the system while it is cold. You may be able to do this with a bicycle pump connected to a bleed valve. (have not tried it on a Citroen), but NEVER presurise above the rated system pressure or you will blow a seam on the radiator.
The overheat lamp in the gauge comes on when going to ‘ignition’ before starting, and stays on, together with the 4 bottom lights in the display, until the engine is cranked.
The lamp often comes on for no reason while driving, together with the STOP lamp.
It’s usually caused by the brown temperature sensor plug needing a clean or tightening.
Intermittencies in the brown sensor wiring also cause the cooling fans to go to high speed for no reason.
The brown sensor is item 8008 on the map, going to pins 7 & 14 of the Bitron.
The lamp often comes on for no reason while driving, together with the STOP lamp.
It’s usually caused by the brown temperature sensor plug needing a clean or tightening.
Intermittencies in the brown sensor wiring also cause the cooling fans to go to high speed for no reason.
The brown sensor is item 8008 on the map, going to pins 7 & 14 of the Bitron.
2002 C5 2.0i AL4 230,000 km 76372389
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
I guessed it was normal but as the handbook doesn't mention it I thought I'd better ask.Clogzz wrote:The overheat lamp in the gauge comes on when going to ‘ignition’ before starting, and stays on, together with the 4 bottom lights in the display, until the engine is cranked.
This did happen to me yesterday though the reason was low coolant level cured by a top up.Clogzz wrote:The lamp often comes on for no reason while driving, together with the STOP lamp.
Thank you
-
- Posts: 4809
- Joined: 11 Jun 2007, 16:17
- Location: Christchurch, Dorset. UK
- My Cars: 2005 C5restyle 1.6HDI 16v 110hp VTR Estate
2008 C5 X7 1.6HDI VTR+ Saloon - x 231
The problem is getting worse. The stop light and the coolant temperature warning light is illuminating more often - usually after acceleration though it also comes and goes at will. As you say, the fans kick in full speed.Clogzz wrote:The lamp often comes on for no reason while driving, together with the STOP lamp.
It’s usually caused by the brown temperature sensor plug needing a clean or tightening.
Intermittencies in the brown sensor wiring also cause the cooling fans to go to high speed for no reason.
The brown sensor is item 8008 on the map, going to pins 7 & 14 of the Bitron
Where can I find the brown sensor, is it on the fuel filter housing? Is that also where the thermostat is? Can the wiring be traced easily enough?
-
- Forum Treasurer
- Posts: 10814
- Joined: 07 Aug 2002, 17:12
- Location: United Kingdom
- My Cars: MK2 '17 C4GP 1.6 BlueHDi 120
'13 3008 1.6 HDi GripControl - x 984
Mike,
I'm sure that's the right part - what ever the BOL says 8)
If you look at the fuel filter, the termostat housing is under it. There will be 2 or 3 temp sensors screwed into it (depending on whether your engine is ECU controlled or not - I suspect it will be). One of the sensors will be brown and have 2 wires going to it (usually front right as you look at the housing) - this is the one that feeds the Bitron. If you unplug it then both fans should roar into life at high speed - note you might need to turn the ignition on to stop the fans again (been there, done that!). I would disconnect it to see the fans come on to know you've got the right one, then clean up the pins and reconnect, then waggle to wire to see if you can generate a fault (is fans come on).
I'm sure that's the right part - what ever the BOL says 8)
If you look at the fuel filter, the termostat housing is under it. There will be 2 or 3 temp sensors screwed into it (depending on whether your engine is ECU controlled or not - I suspect it will be). One of the sensors will be brown and have 2 wires going to it (usually front right as you look at the housing) - this is the one that feeds the Bitron. If you unplug it then both fans should roar into life at high speed - note you might need to turn the ignition on to stop the fans again (been there, done that!). I would disconnect it to see the fans come on to know you've got the right one, then clean up the pins and reconnect, then waggle to wire to see if you can generate a fault (is fans come on).
Richard W
Thanks for that endorsement, Richard.
The BoL probably got its translation from French wrong, as réfrigérant means coolant in French … the engine cooling fluid.
The Bitron casing says ‘Bitron Video’, and the input is too sensitive, picking up interference.
There’s been a free modification with a screened cable in France:
http://xu10j4r.free.fr/xantia/notexantia.pdf
The BoL probably got its translation from French wrong, as réfrigérant means coolant in French … the engine cooling fluid.
The Bitron casing says ‘Bitron Video’, and the input is too sensitive, picking up interference.
There’s been a free modification with a screened cable in France:
http://xu10j4r.free.fr/xantia/notexantia.pdf
2002 C5 2.0i AL4 230,000 km 76372389