What is a car radiator?
Your engine and transmission generate a great deal of heat. Roughly a third of the energy in every gallon of gasoline you pay for winds up as heat that has to be dissipated by your radiator.
A mechanically-driven pump circulates a special low-freezing-point/high-boiling-point coolant through the engine block and cylinder head to remove excess heat, which is passed on to air coming in the grille by the radiator. Vehicles with automatic transmissions generally have a cooler that runs hydraulic fluid from the transmission into the radiator to keep the transmission cool as well. The radiator is mounted in the front of the engine bay, generally right behind the air conditioning condenser and right in front of a fan. Finned tubes run vertically or horizontally from an inlet tank to an outlet tank, connected to the engine by rubber hoses as thick as your wrist.
Radiators are generally of copper and brass construction, or aluminum fins and plastic end tanks. If the coolant is changed regularly, either type of radiator should last the life of the vehicle. Coolant that’s outlived its service life can become corrosive, eating through the metal tubes or making the plastic tanks brittle and prone to cracking. Mechanical damage can also shorten the lifespan of a radiator. In severe cases of failed coolant, the radiator tubes can plug with sludge.
What are the symptoms of a faulty car radiator?
Your first indication of a bad radiator will often be as simple as the OVERHEAT light on the dashboard. A slow leak will leave too little coolant in the system to carry heat out of the engine. More severe leaks will drip coolant onto the ground, generally accompanied by a sweet, moist scent of hot coolant.
If your overheat light comes on, or you detect leaking coolant, immediately pull off the road in a safe place and shut off the engine. Wait five minutes or so before opening the hood to keep hot steam from scalding you. When it’s safe, you can check the coolant level. Some vehicles use a plastic header tank that can be checked visually. Your owner’s manual will have a graphic that shows you where the tank is, and what the level is supposed to be.
Some older vehicles require you to remove the radiator pressure cap to check the level. Use gloves or a large rag, and proceed slowly. Opening the cap may cause the coolant to flash into steam, with the potential for severe burns. If the level is low, you may be able to top off the coolant with ordinary water and proceed to the repair shop. If the overheating is not caused by an obviously low coolant level, you’re going to need a tow. If checking the level is not something you feel comfortable doing, don’t press on—call for a tow.
What is the severity of a faulty car radiator?
An overheated engine can’t run very long without major damage. The first thing that generally fails is the head gasket, an extremely expensive repair. Continued operation with low coolant can score the cylinder walls. A failed head gasket lets coolant into the oil, and oil into the coolant, causing severe engine damage within a mile or two—severe enough to require engine replacement.
The radiator itself, depending on make and model, can run from $150 to over $500 (or more for luxury models). You’ll probably need new hoses, $10-20, and $20 for fresh coolant. Labor should run $100-200. If your old radiator was sludged up, a chemical flush of the rest of the cooling system, for an additional $50 or so, might be necessary.
If you think you need to replace your radiator, don’t delay. Call the Openbay Concierge team at (617) 398-8888, specializing in ASAP repair requests. They’ll get you in, out, and on your way.