i have a 82 vanagon diesel, and i'm having trouble getting a correct cooling reading on the gauge. i have bled the radiator numerous times, but the gauge is never consistant. one day it's in the middle on the light, the next time it reads just above the second line. always after i shut off, there is gurgleing in the radiator.. this doesnt matter if i go on highway, or city. it will get above the red light if i let it idle for any length of time. like i mentioned, i've bled many times, got alot of air out, filled the expantion tank, replaced the cooling resiviour cap. kinda puzzled..