Coolant Color and Consistency Testing

One of the most common signs that your coolant needs to be replaced is by checking its color and consistency. Coolant should be brightly colored as orange, red, green, yellow, pink or blue. It should not be grimy or muddy in color or consistency, but clear and colorful. Before checking your coolant, make sure your vehicle has been turned off for a long time. When the engine is running, the antifreeze becomes hot as well, which, if mishandled, could leave you severely scalded. When your engine, radiator and coolant are cooled off, you can lift up the cap of the reservoir tank or remove the radiator cap to peek inside. If the back of the radiator pressure cap has brown sludge on it or brown crud, it is possible that your antifreeze is bad and could be damaging your engine cooling system. If you see floating chunks of rust or other sludge in either the radiator or the coolant reservoir, or reserve tank, it might be time to replace your coolant. If, however, you are unsure of the color consistency, coolant can be tested with a coolant hydrometer.