How They Work
Radiators pump coolant through the inner components of your engine. The coolant absorbs the heat that the engine produces, and then travels back to the radiator where it is rapidly cooled. The entire cycle is continuous and constant while you drive. On a side note, coolant also doubles as anti-freeze, and prevents your engine from freezing up in cold temperatures.
Since radiators are the primary component of a vehicle's cooling system, it is vital for them to remain in good condition. When a radiator begins to have issues, you will usually start to notice the signs. The most common signs include overheating engines, coolant leaks, low coolant levels, and sludge in the radiator. Look below for a brief description of each sign and why they occur.
Overheating Engine - The most common sign that your radiator is in need of service or repair is an overheating engine. Sometimes, all you need is some more coolant to take care of an overheated engine. But when the overheating persists, it is a sign that your radiator needs attention.
Leaking Coolant - The next most common sign that a radiator needs repaired is seeing coolant on the ground beneath your vehicle. This is usually caused by a leak in your coolant tubes or a crack in the radiator shell, and it is a serious problem that requires immediate attention.
Low Coolant Levels - If you notice that you are refilling your car's coolant too frequently, that means your vehicle is either using too much too quickly, or you have a coolant leak somewhere. Both are serious issues that require immediate automotive repair.
Sludge - You probably won't discover sludge in your radiator on your own. It is more likely that your mechanic will come across it during a routine service appointment or while making unrelated repairs. Sludge in your radiator means there is an excessive amount of contaminants in your coolant. The contaminants will give coolant, normally brightly-colored, to a rusty or oily color. It is commonly caused by a defective transmission cooler inside the radiator. Not all vehicles have this.