Coolant light

[z4dan]

Hi, I did a round trip of over 500 miles today. Yesterday i checked my levels and all seemed ok. It was the first time I check my coolant. On the trip the coolant warning light came on 4 times, twice on way up twice on way back. Strange how this has only happened since I checked the coolant level. Is it possible I upset the reader or something. When the light came on it only lasted a few seconds or so

[Smartbear]

Hi, I did a round trip of over 500 miles today. Yesterday i checked my levels and all seemed ok. It was the first time I check my coolant. On the trip the coolant warning light came on 4 times, twice on way up twice on way back. Strange how this has only happened since I checked the coolant level. Is it possible I upset the reader or something. When the light came on it only lasted a few seconds or so

Checking the level won’t upset anything, you haven’t mentioned if the level was low or not when checking after the warning?
Rob

[enuff_zed]

Having seen an expansion tank cut apart, I can tell you that the float you see popping out the top is a visual aid only. It is not connected to the level sensor in any way. In fact it sits in a cavity that bottoms out slightly higher than the bottom of the tank, I suppose to make you think it's empty that little bit sooner.
The sensor plugs into a 'socket' in the bottom of the tank.
A separate float surrounds this 'socket' and has a magnet in it. When the level goes very low then the magnet trips a reed switch in the sensor and puts the light on.
It may simply be that your sensor is getting old and the reed switch is moving a little over bumps etc. Or maybe the electrical connector is dirty.

Obviously this is assuming that you do still have a tank full of coolant.

[Roberltd2]

Did you tighten up the cap fully after checking the level? I made this mistake after checking the water level for the first time and lost a lot of coolant as a result.

[z4dan]

Did you tighten up the cap fully after checking the level? I made this mistake after checking the water level for the first time and lost a lot of coolant as a result.

Did you tighten up the cap fully after checking the level? I made this mistake after checking the water level for the first time and lost a lot of coolant as a result.

Its quite possible this could be the case as when i checked it on the journey i felt it wasnt solid tight. since then though its not gone off which is strange. maybe it just does it on long jurneys when engine gets hot (sometimes my engine does get quite hot)

[z4dan]

Hi, I did a round trip of over 500 miles today. Yesterday i checked my levels and all seemed ok. It was the first time I check my coolant. On the trip the coolant warning light came on 4 times, twice on way up twice on way back. Strange how this has only happened since I checked the coolant level. Is it possible I upset the reader or something. When the light came on it only lasted a few seconds or so

the level was fine when i checked it before the long journey

Checking the level won’t upset anything, you haven’t mentioned if the level was low or not when checking after the warning?
Rob

[Robin82]

Hi, I did a round trip of over 500 miles today. Yesterday i checked my levels and all seemed ok. It was the first time I check my coolant. On the trip the coolant warning light came on 4 times, twice on way up twice on way back. Strange how this has only happened since I checked the coolant level. Is it possible I upset the reader or something. When the light came on it only lasted a few seconds or so

If the light is still appearing after checking the coolant level and it's persistent I would start looking around the bay, expansion tank, pipes and bottom tray for any leaks/coolant, it may only be a tiny amount but enough to let air into the system. It could be a faulty sensor but I'd say unlikely.

The oem tanks are well known for splitting, although often it's very difficult to tell with the naked eye. I had a hairline crack only 1cm long, practically invisible, but it didn't prevent a sh1t ton of air being let into the system and messing with levels/sensors/air vents etc. The mother of all airlocks and a right pain to bleed out.

I'd also advise checking to see if you're getting full heat from the cabin's air vents. Check the pipes (bottom left of the radiator primarily) when the engines up to temp to make sure you're getting full circulation.