Low coolant warning light

BX Tech talk
User avatar
deltic
BXpert
BXpert
Posts: 622
Joined: Tue Jan 25, 2011 10:48 pm
x 11

Low coolant warning light

Post by deltic »

This now seems to be permanently on, however there is sufficient coolant, no leaks and not overheating. So presumably a wiring problem or failed sensor or could it be something else? Could anyone advise how to test the sensor please?

Given the MOT is due soon I'm guessing this would count as a failure...

Thanks!
1991 BX GTi Auto, grey, 137,000 miles (2015, 2017 & 2019 Citroen Classic Challenge veteran)
2006 C4 VTR+ 2.0 Coupé, silver, 65,000 miles

prm-comp
New Member
Posts: 4
Joined: Sat Feb 08, 2020 8:55 pm
Location: Selsey
My Cars: Citroen BX 16v

Re: Low coolant warning light

Post by prm-comp »

Most of the problems ive found with the coolant level sensor is corrosion building up on the spade
contacts of the sensor and 2 pin cable plug connections. Corrosion builds up due to temperature changes, attracting condensation and oxidises the contacts. (turns green/blue) Non-covered spade contacts are quite prone to this in those situations.
Try, removing the sensor, clean the electrical contacts and probe tips, also the female sockets on the cable plug. Check continuity with a meter between sensor tip and spade connection, also cables on the plug. Add a very small amount of vaseline to the spade contacts when refitting.
Before refitting the sensor, try wetting your thumb and finger and hold the sensor tips. You may get the dash light to flicker.

Regards

User avatar
deltic
BXpert
BXpert
Posts: 622
Joined: Tue Jan 25, 2011 10:48 pm
x 11

Re: Low coolant warning light

Post by deltic »

Many thanks. If I can tear myself away from working from home I'll do some testing...
1991 BX GTi Auto, grey, 137,000 miles (2015, 2017 & 2019 Citroen Classic Challenge veteran)
2006 C4 VTR+ 2.0 Coupé, silver, 65,000 miles

User avatar
vulgalour
BXpert
BXpert
Posts: 492
Joined: Mon Feb 04, 2013 11:30 am
Location: Kent
My Cars: 1980 Austin Princess 1.7 HL
1987 Citroen BX 17RD
x 90

Re: Low coolant warning light

Post by vulgalour »

I'll second prm-comp's comment as that's a more in depth version of what I had to do on mine to resolve the light being on erroneously. I also had to put a cable tie around the plug to hold it onto the sensor to stop it flickering even when all the connections were clean and tight.

User avatar
jamescarruthers
BXpert
BXpert
Posts: 460
Joined: Wed Nov 07, 2012 2:11 pm
Location: Cambridge
x 12

Re: Low coolant warning light

Post by jamescarruthers »

Over on the XM club it is often thought that oil in the coolant stops the probes working, making them non-conductive and the thinking is to use proper blue glycol coolant, not never long life OAT types. I presume this transfers over to BX design in a similar way.
1987 Volvo 480 ES
1992 Renault Master Mk. 1. Machzone Chateau camper. 2.0 LPG

Previous BX's:
A966 XRL -- BX 16 TRS
H767 BEG -- BX 14 TGE
B316 AMP -- BX 14 E