Early morning dumb question:
 

My 03’ 3.0 gets minimal usage. (Has had a headgasket about 15k ago). Low Coolant light comes on about every 100 miles- no signs over overheating (sat in traffic for 20 mins yestrday, no symptoms).

I dutifully top the tank off with a 1/2 cup of coolant mix. The level indicator plunger is always at the full extension before adding.

Admittedly, the overflow tank is Amazons best (cheapest) tank. Any possibility the float, sensor, anything else just might not be functioning properly? I think I read somewhere that the magnet gets loose or something.

There are never any drips or smell associated. Doesn’t appear to have coolant in cylinders based on recent testing.


Sent from my iPad using Tapatalk

If the pecker is full height then you are over filling. The magnet switch is a separate float at the bottom. Sounds like you have a defective switch

I keep the top of the indicator plunger even with the neck of the ET. The expansion tank needs plenty of room to expand..

If you are losing coolant, and it sounds like you are if you are adding anything, you are losing coolant, and you should find out why...UV testing kit...

If the low coolant light is coming on and the indicator is level with the neck of the tank, then the sensor or wiring is bad. Double check it with UV dye. As others have said.

If you are adding coolant and the level indicator is already "full," it will just blow the extra coolant out the overflow during the next drive and it will continue to be "full" next time. If that is what you are seeing every time you fill it, I'm with Andrew that the magnet switch is bad.