I've got this brown sludge in the bottom of my coolant overflow tank where the dipstick is, since I've owned the car. I flushed the radiator and refilled it, but it's still there and really bothers me... I've heard that it can be from mixing coolants and seeing as I didn't flush the heater core, it's probably made the problem worse. (but no obvious change, it does look better since my flush of the radiator about 5 months ago when I got the car) I can flush a radiator and all that, but my main question is how to flush the heater core. I've done some research and they say don't use chemicals, don't use compressed air, don't use high water pressure, etc. But my problem is that I don't know where/which hose I'm meant to be flushing through or disconnect either. Does anyone else have a VT comoddore that'd be willing to take a couple photos for me to help out. My car doesn't overheat or anything, it's running perfectly, but I don't like the fact that it's there and could be slowly creating more problems for me in the future and more problems = more $$$ Thanks Guys. Bronson.