i suppose not a good thing if radiator fluid brown & dirty right?
Nope, probably a lot of rust from not changing the coolant. Flush it a few times till ti runs clear and then add 50% coolant to 50% distilled water. If you suspect the radiator is clogged or rusted beyond repair, replace. When was the last time the hoses were changed? Might want to replace those too.
Tom is right, as usual, but very often Ethylene Glycol looks brown and dirty. . Propylene Glycol is the green stuff. Toyota uses a special blend, make sure when you buy antifreeze it says on the bottle it specifically says for use in Toyota vehicles.
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