E46 Coolant Light over 160

[Jive_E46]

Hello

As the title suggests, was driving in my friends E46 M54B25, noticed that the coolant light comes on after driving at 159KPH for more than 10 minutes. We have tested this about 6 times and it’s the same result-The light goes on but as soon as we slow down to 120KPH - the light goes off.

Is this an electrical gremlin or is there an issue with the cooling system (coolant level sensor, water pump)?

We also check the coolant level in the mornings and it’s full.


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[CK4LIFE]

Maybe the car doesn't like going over maximum speed limit.... 😂
Sensor could be suspect

 

[Tinuva]

Its normal if the coolant level is almost but just just below the correct level.
I have seen this too, but even just at 140 or lower speeds in the summer months, more to do with the revs I think.

What happens is, when the engine works hard, it needs more coolant flowing so I think if you could watch the level while driving like that, the level will actually dip as the system pumps the coolant faster through the system. Then when it slows down again after its ok as you noticed.

I wouldn't worry about it too much, unless you plan on tracking often.

 

[evnmopwr]

This happened to me 1 week after o done the 330i swop on my touring.
went on holiday to knysna.

As along as i cruised at 120km/h, the light would not go on.
If i pushed 140, it comes on.

After getting to destination, without incident thankfully, the next morning i bled the cooling system and i never seen the light again

So could low level at higher speed or Air bubbles in the system possibly.

 

[Coisman]

Ja, that is the Spietkop Safety Anti Speeding Device activating to keep you driving the legal speed. 🤪👮‍♂️

Could be the Thermostat I think not working properly, or even water pump not doing it's job on higher speed and RPM.
Might also be the little sensor at the back of the engine (Water Temp Sensor), and check the one on the coolant pipe as well under the window washer bottle.
I have replaced all these on my car.
Might be a good thing to have the car read for errors as well.

 

[Jive_E46]

Thanks for all the great advice Fanatics, will look into the above


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