Posted on: 2 May 2019Share
Whether your engine temperature gauge is slowly climbing into the danger zone, your engine automatically shut off due to overheating, or you've got white smoke billowing out from your car hood, you've encountered every driver's worst fear. When your engine overheats while you're driving, it's a major roadside emergency.
Overheating is typically caused by a failed radiator, which is responsible for keeping the engine comfortably cool. When the radiator doesn't function, there's no way for your car's engine to dissipate heat — it will always overheat when you're driving it. You'll need to have your radiator fixed by an automotive repair service as soon as possible since overheating can easily cause permanent damage to your engine or your transmission. What causes car radiators to fail, and what should you do about it? Read on to find out.
What Does a Car's Radiator Do?
In order to understand how a car radiator can fail, you should first know a little bit about how it works.
A car's engine generates an incredible amount of heat while it's running, and it's the radiator's job to keep it at a safe operating temperature. Some of the heat generated by the engine is transferred to the coolant running through it, which is circulated into the radiator by a water pump. The radiator consists of several long, thin tubes that have air blown over them by a fan — this rapidly brings the temperature of the coolant down. The water pump continues circulating the cooled fluid back into the engine, where it can absorb some of the engine's heat again.
Why Do Radiators Fail?
The most common reason why radiators fail is a coolant leak. A small pinhole leak in the radiator hose or a crack in the radiator itself will cause it to slowly leak coolant. Low coolant levels reduce the fluid pressure in the radiator, so the water pump connected to the engine isn't able to circulate coolant from the engine to the radiator as quickly, resulting in poor cooling performance. Additionally, low coolant levels also mean that less thermal energy is transferred from the engine to the coolant, which also makes your engine more likely to overheat.
It often takes quite a while for coolant leaks to noticeably affect the cooling performance of the radiator. You may be able to recognize a coolant leak by the smell — check for a sweet smell in your engine bay or underneath your car. Coolant is a mixture of sweet-smelling antifreeze and water, so using your nose is often a reliable way to detect coolant leaks.
Another common cause is a failure of the radiator fan. This is more likely to happen if your car is old — sometimes the bearings in the fan simply deteriorate to the point where the fan can't turn anymore. With no air blowing over the radiator, the coolant simply becomes hotter and hotter until it's no longer able to cool down the engine.
Rarely, you may also experience a water pump failure. The water pump has an engine drive belt connected to it which turns rotors on the water pump, circulating coolant from the engine to the radiator. Like with the radiator fans, the bearing on the water pump can also deteriorate and prevent the rotors from moving. With no coolant circulating through the radiator, your engine will quickly overheat.
Should You Drive Your Car When the Radiator Doesn't Work?
No, it's not safe to drive your car when the engine is overheating. Continuing to drive an overheating car is a major risk — overheating can cause permanent damage to your engine. Worse, your engine may suddenly seize up while you're driving and cause you to lose control of your car — this can easily result in a very dangerous situation.
Have your car towed to an auto repair service instead of attempting to drive it. The most common cause of a failed radiator is a leaking radiator hose or a crack in the radiator, and both of these are very simple and inexpensive to fix. Replacing a radiator fan or a water pump is slightly more involved, but it's still an inexpensive repair. Replacing or rebuilding your engine or transmission because it was severely damaged by overheating, on the other hand, is incredibly expensive. It's not worth risking further damage to your vehicle by continuing to drive it while it's overheating. Call a towing service and have your radiator fixed by a professional mechanic.