Your car’s engine is made up of dozens of different parts all working together to make it work properly. One of the most obvious and best-known by-products of your car’s engine is heat. The heat exchange in your engine is important, and one of the components most intimately connected with that process is the car engine fan, also known as a car engine cooling fan.
In today’s blog, we’re looking at what these fans are, what they do, what different types exist and how to tell when yours is experiencing problems. Consider this blog your unofficial guide to everything related to your car engine fan.
What is an Engine Fan? How Does it Work?
The engine cooling fan, sometimes also known as a fan clutch, is a component typically located either in front or behind the radiator. The fan is typically just freewheeling when the temperature in the engine is low and then kicks in when the temperature rises. In some cars after a long drive, you might stop, turn off the engine and get out of the car but still hear a humming sound from under the hood, which is typically the fan still at work to help cool the engine back down faster.
That delayed function is important because it’s actually crucial for the engine to warm up properly first to ensure it works safely and properly. Cooling it at the early stages is not good for the overall engine function. The fan itself is driven by a belt and pulley that are connected to the crankshaft. When engine temperature reaches a certain predetermined level, the fan kicks in properly, drawing in more air and blowing it to maintain a safe temperature or even slightly lower the temperature until it returns to acceptable levels.
What Are the Different Types of Engine Fans?
Broadly speaking there are two types of engine fans, mechanical and electrical. The former is further divided into two types, which we’ll describe in more detail in this section.
Flex Fan
A flex fan is the first type of mechanical fan commonly used in cars. They contain a steel frame and the blades are usually either plastic or steel, but sometimes another material. Unlike their mechanical sibling the clutch fan, the flex fan doesn’t use a clutch and works at the same speed as the water pump. As RPMs get higher, the blades also flatten out to allow for optimized cooling but with less drag than you might get on a clutch fan. This makes flex fans ideal for modified and/or higher-performance vehicles.
Clutch Fan
The clutch fan works in conjunction with a thermostat and uses a clutch to either engage or disengage at specific speeds, RPMs or temperatures. At any one time, the clutch fan is spinning at around a third of the speed of the water pump, and the clutch continues to limit its top speed, whether engaged or not. The construction of the fins is a lot more straightforward than the flex fan, but it has a solid cooling ability and still works up to about 6,000 rpm without too many problems. The flex fan manages up to 8,000 rpm.
Electric Fan
The first difference with electric fans is that they are not powered by the engine’s mechanical power, but rather by your car’s electrical system. This means that they do add a drain to your car’s electrical system, but it’s not dramatic. One advantage that people talk about with electric engine cooling fans is that they don’t cause a parasitic loss in horsepower, which some mechanical fans can do.
The electric fan works well in high-horsepower cars, and will also prevent the wear and tear on your water pump that happens with mechanical fans. What’s more, the engines are generally more fuel-efficient and live up to their real power ratings without the drain on horsepower.
Which Engine Fan Type is Best?
On the surface, for many people, the electric fan seems to emerge as a clear winner of the three fan types, but the truth is a little more complicated. No one fan is universally better than any other. How effective and worthwhile each fan is depends on the horsepower rating, how modified the engine is and how you use the car. For a daily runaround with stock engines that is used for commuting, school runs and weekend day trips, a mechanical fan is fine.
Those driving a slightly modified or tuned engine with a boost in horsepower will find some efficiency benefits in the flex fan. Anyone with a high-performance vehicle interested in gaining more of a balance between power and cooling can use an electric fan.
Symptoms of a Bad Engine Fan?
How do you know if and when your engine fan is in need of the professional attention of a mechanic? Look out for any of the following signs.
- Scraping or Squeaking Noises – Do you hear a scraping sound or squeaking/squealing when you have the fan on? It may also appear as a loud clicking or a strange whirring kind of sound. It indicates that one or more of the fan blades are damaged and might be making physical contact with other components.
- Overheating – If you suddenly notice that your car’s engine temperature is getting too hot, then it could be a sign that the fan has suddenly stopped or that it’s not operating at full capacity.
- Your A/C is Suffering – One other function of the engine cooling fan is to draw air through the A/C condenser and take heat from the refrigerant. If your A/C isn’t working well and you notice other symptoms in this list, then you can put 2 and 2 together.
What Causes the Engine Fan to Fail?
Engine fans start to fail for a number of reasons, but most common are the following issues:
- Blown cooling fan fuse – check the fuse board to see if you can see a burnt-out one
- Defective temperature switch
- Faulty coolant sensor
- Engine thermostat is stuck open
- General wear and tear in the fan blades
Can I Drive My Car if the Engine Fan Isn’t Working?
It’s not safe to drive your car without a working cooling fan. Overheating is a major cause of engine damage and even engine failure. You might be able to take a short (and slow) drive to the auto shop, but beyond that it’s not a good idea.
How Much Does it Cost to Replace a Car Engine Fan?
Unfortunately, replacing a car engine fan isn’t so cheap. It should cost around $465 in parts, and a further $120-150 in labor, and quite possibly more depending on various factors. Needing a budget of $600 to replace the car engine fan is not an uncommon scenario.
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