low coolant light

I have a 98 regal 3800
450,000 km oil changed every 3 weeks.
I had a leak in the bypass pipe that goes through the tensioner and changed all.
Now the low coolant light will come on after about 1 hour(blinking)
The next hour it will decide to turn off or be intermitent. Then for the rest of the day it stays on solid.I get home and wait a bit and check it is full of coolant.

I turn on the car and now the low-coolant light is back to blinking?

It is probably the rad but I am looking for idea's.

Cheers

Check the coolant sensor itself. It's the square box looking device on the passenger side radiator tank about 1/3 the way down. Many times they get mucked up with sludge and will cause what you describe.

Check the coolant sensor itself. It's the square box looking device on the passenger side radiator tank about 1/3 the way down. Many times they get mucked up with sludge and will cause what you describe.

will do thanks.