In short: Got a new expansion tank and low coolant sensor, and now the coolant light comes on and stays on in spite of there being plenty of coolant.
More details will be of importance below...
My 1999 S70 (otherwise known as Sophie the Sweedish Fish, for her lovely red color). I recently changed the expansion tank to fix a leak which worked. But as I changed the tank, I saw that the previous owner had yanked out the coolant sensor wires and twisted them together (see pic).
That is when I realized I should replace the sensor, especially because my Low Coolant light never came on when I had low coolant... which is dangerous.
Previous owner must have done this to make sure the light never illuminated while trying to sell the car as: "Totally Not Leaking Coolant, Everything is Fine!
" But it wasn't fine, it had coolant leaks from the heater core and expansion tank. But I fixed all the leaks and she is good as new, however...I got a new sensor and plugged it in... I started the car. The light came on normal pre-ignition illumination and then went off, and stayed off.
I was happy thinking that everything was fine. The next time I turned her on, the light came on normal pre-ignition illumination, then went out for about 3 seconds... then came back on
and stays on for the entire driving time. Never goes off. I have now been driving her for about 2 weeks, and each time I start her, the light keeps coming on 3 seconds after ignition and stays on.So what may be the problem? I checked the expansion tank's little low coolant "floater" is not stuck, it moves up and down freely. I don't understand why the sensor is reading "low coolant"
Any help?? Thank you in advance!