How do I know when the antifreeze/coolant is low in the radiator of a 2003 kia optima?
Your owner's manual likely has the information you need... That being said I googled for an image of your engine bay, this is what I found... Two red circles are on what appears to be the radiator cap (lower right) and coolant reservoir (upper left)... When the engine is cold fill the radiator full with 50/50 mix and the coolant reservoir between the hot and cold marks... (May be max and min or similar on your car) Before filling the reservoir make sure it's the coolant reservoir and not some other fluid, I'm fairly certain it is but I don't have an actual car in front of me, it looks like it has decals on the top and the cap should indicate what it is.
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