i have a 87gmc vandura and the radiator overflow jug the line that say on it full cold.i fill it to that line?

Question

and about a week later it's gone is this normal?

Answer 1

Fill to line when cold.

Answer 2

THE COOLING SYSTEM COULD OF BEEN LOW IN THE SYSTEM IT SELF. SO WHEN IT GET HOT THEN COOLS DOWN IT WILL TAKE FROM THE BOTTLE. IF YOUR NOT LEAKING ANY OR BURNING IT THROUGH THE ENGINE IT MIGHT OF SLOWLY EVAPORATE AND JUST NEEDS TO BE TOPPED OFF