Coolant Level Warning

[Autoglym 255]

As the title says, I have intermittent fault coming up on my OBC, stating"Check Coolant Level"

the level is fine, any one else encountered this, should I just replace the sensor??

regards

Barry

[M3AN 4015]

lol yes. I replaced the entire cooling system on my daily the other week and checked and cleaned the level sensor. Worked great for 4 days then decided to stop working... :-/

If I replace it now I'll lose litres of fresh coolant and have to fill up bleed the system again... not going to happen in the short term. So I'm living with the warning.

This is from BMW's TIS but you'll be working pretty blind:

Quote

Situation:
A substantial number of coolant level switches are being replaced under warranty. The most frequent dealer comment is "coolant light is on, replaced coolant level switch". A detailed investigation of the replaced parts showed that more than 60% of them were non-defective.
Action:
It is necessary to ensure that the cause for the complaint "coolant light is on" is due to a defective coolant level switch before replacing it.
Procedure:
When a vehicle is brought in with the complaint "coolant light is on", use the following method to identify a defective coolant level switch:
 

1. Open the cap of the radiator/expansion tank and locate the coolant level switch mounted in the bottom. Use an appropriate piece of wire to slide the float up and down. Ensure that the float moves easily and stays in the up position by itself while the coolant level is correct. If the float sinks in the coolant, the coolant level switch has to be replaced.
2. Disconnect the cable connector on the coolant level switch and connect an ohmmeter to the both contact pins of the installed coolant level switch. Measure the ohmic resistance of the coolant level switch in both float positions. The following resistance values indicate a defective coolant level switch, that has to be replaced:
   • Float up: resistance more than 1 ohm
   • Float down: resistance less than 40 k/ohm
3. If the coolant level switch shows correct resistance values in both float positions, check the cable connector for corrosion or soiling. Ensure proper electrical contact and connect the cable connector again.
4. With the ignition on, slide the float down until it stops and hold it in this position. Wait at least 20 seconds and turn the ignition off. A coolant level warning should be displayed in the instrument cluster/information display.

Let the float slide back to the up position. Turn the ignition on, wait at least 20 seconds and turn the ignition off again. The instrument cluster/information display should not show a coolant level warning.

 

[Autoglym 255]

Ok, thanks for that, mine is probably due a coolant change anyway, so have ordered a sensor & sort it

Thanks Again

Barry