95 Saturn SLi auto, 160 k Miles. My low coolant light and high coolant temperature light flash together when I drive my car. The coolant level is fine and the engine does not overheat. The coolant temperature sensor was replaced at the dealer about 2 years ago and everything seems fine. Does anyone know what would cause both lights to flash?

 

The low coolant light is most likely from the sensor in the reservoir sticking from crud after 12 years of anti-freeze. Best suggestion is to remove the reservoir completely and fill partway with a solution of HOT water and dishwashing detergent, sloshing it around and repeating this until the water runs out clear. You won't damage the sensor float that actually moves up and down a tube containing the electrical ciricuitry insulated from the anti-freeze. This should work otherwise the reservoirneeds to be replaced, either from a junk yard or new one from the dealer


Don't know about the high temperature light.

 

Its a good idea to clean the coolant resevoir each time the coolant is changed. Saturns orange coolant is saposed to last 5 years.

 

I took off the reservoir and cleaned it out and both lights stayed off for about a day so I thought everything was fine. But then today they came on only for a little bit and they've been off. So it must be the reservoir float sticking. I guess if it comes back on i'll have to get the reservoir replaced like you said. Thanks everyone for your help!

 

I have the same exact problem- low coolant flashes, but car isn''t
overheating. Did you ever find a fix?

 

Its the float in the reservoir tank. Remove the tank and clean it out. If its been doing it a while, you might have to replace the tank.