Do all Citroens lie?

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beemernut
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Do all Citroens lie?

Post by beemernut »

I have an XM that, since the day of acquisition, has had the low engine water warning light come on. On the first occasion I called out the AA, only to be told it was lying. It has consistently lied to me ever since. It's not a permanent thing. It lulls you into a false sense of security and then, "ping", on comes the light when you least expect it. There's plenty of water in the header tank and no pressure build up when you take off the cap.
I also own a BX Diesel which has recently had the head skimmed and replaced and, lo and behold, the engine water light has started coming on intermittently. It also has plenty of water in the radiator and no pressure build up when you take the cap off.
Is this just something I'll have to live with or is there something my cars are trying to tell me?
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AndersDK
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Post by AndersDK »

yes -
Citroens with this kind of water level warning circuits - has a very naughty habit of lying [}:)]
The circuit is trying to tell you a tale : something IS in fact wrong !
From late '80-es Citroen modified in general all car's coolant level warning circuit - to incorporate a warning for wiring fault in the sensor circuit.
The old circuits had a simple switch acting sensor - which with a faulty sensor was fatal to engine in case of water loss.
With this kind of circuit - an electronic relay is incorporated - instantly turning on the warning if :
1) water level lo
2) sensor disrupted
3) sensor cabling/connectors disrupted (corrosion)
Usually the sensor fitted in the header tank is simply 2 stainless points - relying on the lower ohmic resistance in the coolant to "shortcircuit" the points. This is inverted in the electronic relay - only giving warning with open circuit - i.e. dry sensor points.
But if the cabling/connector to these sensor point go open circuit (corrosion) - you have the same situation - and you also get a warning !
A third option is dirty/contaminated sensor points - again resembling dry sensor points - thus again : warning !
You should therefore do :
1) clean the sensor points inside the header tank - using a brass brush.
2) clean/rub all connector pins - both on header tank & electronic relay.
3) inspect cabling suspeciously - if cabling (cupper) has gone black under the plastic isolation - it's new cabling !
And I'm talking ALL cables to/from electronic relay - not just sensor cabling [B)]
It's important you regain confidence to this warning light - as the engine overtemp warning lamps simply comes on too late !
On PSA engines these 2 engine temp warning levels have the following meanings :
level 1 : your head gasket will blow within 10 sec's
level 2 : Please call your garage for arrangement of replacing the headgasket.
jkirkwood
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Post by jkirkwood »

I can only think of one thing more hideous than auto electrics; French auto electrics.
jkirkwood
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Post by jkirkwood »

Come to think about it I <b>can</b> think of something even more hideous than French auto electrics; French auto electrics in a Haynes manual.[:o)]
beemernut
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Post by beemernut »

Anders
Have sorted out the BX - the connections to the switch were cooroded, have scraped them clean, sprayed with contact cleaner and WD40. Light now not coming on except when the ignition is first switched on. Will have a go at the xm at the weekend.
Many thanks for your advice
Beemernut
tecw1979
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Post by tecw1979 »

hmmm... french auto electrics ... hayne manuals hate them too... they just make up some random gobbledeegook in the zx book i have.
alan s
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Post by alan s »

The secret to reading a H*****s manual is to remember where you took it all from so that when you get to the last sentence, you won't have any problems.
"Reassembly is the reversal of removal." which is on par to saying "night will follow day"...common sense when you think about it, which then begs the question: why buy the b@#$%^& book in the first place. [:p][:p][:p][:p][:D]
Alan S [:o)]
G4EIY
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Post by G4EIY »

Anders,
Reading this item with interest, I have the same problem. can you give a location of the electronic relay on the BX.
Thanks
Brian
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AndersDK
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Post by AndersDK »

Brian -
No problemos - but it's so much easier if people would put their specific model/year in the bottom signature line [:p][:p]
(can be done as a standard signature on your own profile page)
On a BX you'll usually find the relay either on LHS of radiator (standing in front of engine) or near the pressure tank if fitted. Thin gauge wiring. Don't mistake the heavy gauge wiring for the fan thermo-switch.
Depending on various options fitted (e.g. A/C) - it may be hidden somewhere else - follow the thin wires from the sensor then.
On the BX this "relay" is a somewhat long matchbox shaped housing - may be different designed on later generation Citroen models.
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Post by G4EIY »

Anders,
Points noted,and updated, the car in question was the BX Turbo Diesel.
Electronic relay located to the left of the rad when looking from the front of the car, fault found, one slighty corroded contact.
Noted that the CMOS device inside the box is the same as the older BX, but with different pc board.
I assume these are not interchangable ?...
thanks again.
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AndersDK
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Post by AndersDK »

Why not ? [:)]
The function & connector pinning may perfectly be the same -
But the actual circuit may have been updated at some points - for either reliability or production cost reasons - or from a different supplier - very common.
Note that over 1mill BX's were produced - over 12y's.
You'll see endless small variations on allmost any bits on the BX.
G4EIY
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Post by G4EIY »

Anders,
The reason for saying were the older relays usable, was your comment in your post dated 31st July " from the late 80s"..
The spare that I have is from a Mk 1 BX.
I will give it a try later. [:)]
Thanks again.
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AndersDK
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Post by AndersDK »

Ok - got your point [:)]
May simply be my in-accurate expression "late '80-es".
I donno precisely when this electronic relay was fitted to the BX coolant sensor - but the fact it's found on a Mk1 - indicates it's the same functional circuit.
Good luck with the fiddling - it's important you regain a reliable coolant level warning - keep posting if stuck [:p]
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Post by nigelc116 »

I've got the same problem with a xantia 1.9 TD I've even swapped the water level sensor with a mates and the problem went away but....

Today the light came on (it's the one at the top of the temperature gauge) together with the stop light the engine was cold. I could hear the fans running flat out. The header tank is definatley full of water!!

This continued till the engine was warm 75 to 80 deg's on the gauge.

The only way I can get the lights to go off is to rev the engine hard at 3-4000 revs. Then the light goes off for a while.

Help me please it's driving me mad
Xantia 1.9TD Estate R Reg 1998, Green
Gammy leg
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Post by Gammy leg »

Chaps,

Had the very same happen with 2 synergie's and both header tanks were full at the time. My current one has only done it once and that was about 18 months ago so not a major problem.
I have just returned from annual hols down in S/W France and while driving back on superbly smooth and almost deserted french motorway was thinking just how good the old bus had performed, the engine managment warning light came on followed almost immediately by a loss off power under throttle. Couple of seconds later light goes off and power is restored. Most odd I think. 30 seconds later the same thing happens, light on, power off. Then low level fuel light comes on.
To cut a very long story short, the old girl was running on vapours even though I would normally get about 30 - 40 miles notice via the low level warning light for some reason it decided this time not to come on until it was literally out of gas..... Lies, damn lies.
I managed to limp 6km to the next service station and after initially thinking that I had a leaking fuel pipe ( mistook Aircon condensation drippage as diesel ) filled up with diesel and continued without further mishap.

Reference Haynes wiring diagrams, the old Renault ones were excellent cos they had a little picture at the end of every wire so you could tell where it went from and to. The Citroen ones have always been absolutely crap as they are all drawn using correct electrical symbols.

Regards to all

Gammy.
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