I had a similar problem; Low Coolant light was flashing on my Chevy Lumina 2000. My coolant reservoir tank (not the radiator) had sludge/dirt on the inside walls of the tank. So what I did was 1) emptied the reservoir using a kitchen baster (you can get that in a Dollar store), 2) cleaned/removed all the dirt (using a cloth and a bent copper wire); make sure you remove most of the dirt inside the reservoir tank. Voila, the flashing light stopped blinking. So I think what was happening was that when the coolant used to get hot, the dirt from the reservoir tank used to block the Coolant Level sensor making it to blink. That fixed the problem. If this does not fix the problem, then try cleaning the Coolant Level sensor itself which is located on the side of the radiator itself.
Originally Posted by JessicaRebel
Went to go to the gas station tonight and when i turned the car on the low coolant light started flashing. It hasn't done that at all today. It is always kept filled. I just had the ac compressor fixed yesterday. I opened the coolant reservoir and there is this... brown stuff in it and it looks like it is sitting on top of the green coolant. There are little bubbles and you can see the green under them. Anyone have any idea what it is? I have never had this problem before. My radiator does have a small itty bitty leak. I know they are not the best pics but I am trying to figure out if it is oil or possibly rust or god knows what. The pic of the paper towel on the tip is what it soaked up from the reservoir tank. And sorry the pics are not the best, took them on my cell. I checked the radiator cap and on the underside of it seemed to be oil. Could the place i took it for repair screwed it up when changing out my ac compressor somehow? The car is a 2000 pontiac grand prix GT. I am at a complete loss
