C8 Diesel Stop Light And Temp Light On?

[ElaineMK]

Hi everyone.  I have a C8 diesel and the other day the red stop light came on also the water light.  Managed to get home and filled up with water.  Light still came on.  Water tank empty again so topped it up.  When my partner came home he looked and the tank was empty again so he topped it all up and ran the car for a good half hour.  He thought that he's done it, but today taking my daughter to school the light is on again !  I can't see a leak from anywhere?  Can anyone help pleeeeease?

 

[paul.h]

Welcome to the forum.

 

I take it it is the engine coolant that is being lost and the water tank is the coolant expansion tank. If you can not find any leaks including from the water pump, an engine block core plug, into the cabin footwells from a heater matrix leak, from the front engine radiator or into the engine oil, then it may be the engine head gasket has failed and the coolant is being lost in to one of the engine cylinders - if so you may notice more steam than normal from the exhaust pipe and possibly poor running. Also check if the coolant in the tank is boiling indicating possibly the tank cap is not holding pressure or the head gasket has failed.

 

If the coolant does run out there is a risk of the engine overheating and the cylinder head being damaged. Also when you top up the level if it has gone very low you should make sure any air is bled out. Ideally you will top up with anti freeze now we are starting to get freezing weather but the problem needs sorting asap.