Coolant Level Light

[Going Slowly]

I have a 1995 C200 with viscous fan unit.
The coolant low level warning light is staying on despite there being plenty of coolant. I have so far changed both the coolant level sensor and the washer bottle sensor.(both original MB parts)
Now.. If the washer bottle is low the coolant level light stays off after start up, but if the washer bottle is topped up the coolant level light comes on and stays on after start up
Any further help would be appreciated
PS Is the coolant level sensor supposed to sit in a dry sleeve or is it supposed to be wet - this is the rad with the intefrated header tank on top?

 

[Chiefwigum]

Inside the expansion tank, when you take the cap off, there is a level indicator. Its just a centimeter wide lip that stick out. The coolant level needs to be up to here to keep your light from coming on. I think it is just pure coincidence that anything you do to the washer level is effecting your coolant light.

Top it up to the correct level and see how you get on. If the level keep dropping it is likely that you have a leak. They generally leak where the expansion tank joins the main body of the tank.

The coolant sensor sits in a wet bed.

PS The reason the coolant level light is on when going slowly is that the pressure in the system is lower so the coolant level in the expansion tank is lower. I believe your level is just slighty low and if you topped it up to the correct level your light will stay off at low and high speeds.

 

[Ellsy Tanners]

I think you have a wiring fault or poor connection at one of the sensors. If you have replaced both of the sensors then it does'nt leave much.

 

[mattkh]

Hi
Is the car overheating by any chance ?
Just wondered it this indicator has a dual purpose.

 

[Going Slowly]

No overheating whatsoever. I think Ellsy is probably right so will have another look at it tomorrow. Failing that I am thinking of sacrifycing the washer low light for the sake of a coolant level light that will then work.

 

[television]

Water in the electric fan module under the bumper near side can cause this as can water in the control box with 2 lids

 

[mattkh]

Water in the electric fan module

Hi
Thank you.
But why should the fan module have anything to do with water level in the bottle ?

 

[television]

Hi
Thank you.
But why should the fan module have anything to do with water level in the bottle ?

On cars where they have the electric fan as well, the control box for this fan will put that light on, I know it sounds daft, but its fact and in the MB worksheets.

The other one if the sensor is OK and the level correct is that water gets into the control box with 2 lids and water gets in under the modules. there is a mod for this