This is probably really dumb, I am preparing to flush to coolant on my 87 NA, The add coolant light comes on sporadically when cold and the sensor is still good and it has plenty of coolant so I am going to flush it right?

Now the really dumb question where do I put new coolant in? Top of the radiator? The resevoir? The cap on the coolant tube that goes to the top of the motor?

Thanks, I didnt see this stuff in the FAQ.

 

Flushing it won't fix a light.

Fill it through the cap.

Replace the sensor, the rad cap, the thermostat, and then change your antifreeze. Make sure that the hose from the cap to the overflow/recovery bottle isn't leaking.