Kenworth Metal cooolant Tank

[JimT]

Is that an expansion/overflow tank? My pete has a metal tank with a little sight glass. It's a real PITA trying to monitor the level in the tank. All I know is it's either below the glass, above the glass or right within the small window of the glass. I wish I could replace it with a see through plastic tank so I can more easily monitor what is going on without any guess work. Just my 2 cents.