Little Known Questions About Fan Clutches.

Fascination About Fan Clutches

Engine fan with viscous drive A fan clutch is a thermostatic engine cooling fan that can freewheel at low temperature levels when cooling is not required, allowing the engine to warm up much faster, easing unneeded load on the engine. As temperatures increase, the clutch engages so that the fan is driven by engine power and moves air to cool the engine.


This conserves power, because the engine does not have to totally drive the fan. However, if engine temperature increases above the clutch's engagement temperature level setting, the fan becomes completely engaged, therefore drawing a greater volume of ambient air through the automobile's radiator, which in turn serves to preserve or decrease the engine coolant temperature to an appropriate level.


This is simpler to achieve because the engine is mounted longitudinally, with the belt accessory components installed facing the radiator. The fan is installed on the crankshaft sheave or one of the accessory pulleys (e. g. the water pump pulley-block) and will spin in between the radiator and the engine, drawing air back through the radiator and blowing it over the engine.


On the other hand, in a front-wheel drive vehicle, the engine is generally mounted laterally, with the crankshaft and normally all the significant device shafts parallel to the front axle, so regarding directly drive the transaxle; a fan mechanically mounted on an accessory pulley-block would blow sideways and would not deal with the radiator.


The conversion of mechanical energy to electrical energy and back to mechanical rotary power with a fan motor is less effective than a direct mechanical connection, however this is more than compensated by higher control of an electric fan through electronic thermostatic controls which can turn the fan totally off when the engine temperature is below the setpoint.

Fan Clutches - Questions

Some clutches are electronically managed (instead of bi-metallic strip). These provide the prospective to control the level of engagement depending on any number of inputs. Typical managing factors might include engine oil temperature, transmission oil temperature level, coolant temperature level, AC system pressures and ambient air temperature.




When you consider a vehicle cooling system, the very first thing that likely comes to mind is your radiatoror possibly your cooling fan. The oft-overlooked doesn't get a ton of credit or attention, however it's an important piece of the cooling formula in lots of cars. It assists your cooling system run effectively and your engine run effectively.


A fan redirected here clutch is a temperature-controlled coupling in between the water pump shaft and the fan which allows the fan to be functional at low speeds and disconnected at higher speeds. This enables the engine to operate more effectively by getting rid of the load that the fan put on it. So how does it work? It really depends upon the design of fan clutch you pick.




Non-thermal clutches run solely based upon the shaft speed of the water pump. At low and idling speeds, the clutch permits the fan blade to turn at practically a 1:1 ratio. At high speeds, the silicone fluid within in the clutch will lose its capability to transfer the energy from the shaft to the fan clutch body (and for that reason, the fan) and the fan is then allowed to almost free-wheel, eliminating its load from the engine.


However, non-thermal clutches are a lower-cost choice than thermal-style clutches. The thermal fan clutch runs in reaction to underhood temperature levels. As hot air blows our website across the radiator, it heats a thermal spring installed at the front of the clutch. As the spring is warmed, it turns and enables valve ports to open within the clutch.

Facts About Fan Clutches Revealed

This engages the clutch and drives the fan. When the engine is cooled down, the thermal spring turns back and closes the valve ports, disengaging the fan. The speed at which a thermal fan clutch spins a fan depends mainly on the exact fan you pick. On the Summit Racing website, for instance, you'll find three various kinds of thermal fan clutches from Hayden alone: This design turns the fan at 60-70 percent of the water pump shaft speed when engaged, and 20-30 percent when disengaged.


This fan design turns the fan at 70-90 percent of the shaft speed when engaged for increased cooling. When disengaged, it turns the fan at 25-35 percent. Source It's utilized with deeper-pitch fans (2 1/2 of pitch), and works well with greater operating rpm. Serious duty thermal fans turn the fan at 80-90 percent of the shaft speed when engaged and 20-30 percent when disengaged.


This design of fan clutch operates like a thermal clutch, however the ECM/PCM signal controls the level of engagement of the EV clutch. fan clutches. This engagement process is ultimately controlled through the ECM/PCM by the following input variables: Coolant Temperature, Intake Manifold Temperature Level, Transmission Oil Temperature Level, A/C Pressure and Engine Oil Temperature Level.


Like all components, fan clutches will break and need replaced. According to Hayden, here are some signs your fan clutch might require replaced: Fan spins excessively when engine is stopped (three or more times when hot engine is turned off). Poor A/C performance at idle or low lorry speeds.


Fan speed does not increase up until engine is exceedingly hot. Fan blade suggestion moves more than 1/4-inch front to back (fan clutches). Fan turns roughly or does not turn at all. Excessive fan sound at all speeds due to failed bearing. Vibration that increases with engine speed. Leaking fluid or oily develop around the bearing or thermal spring.

All about Fan Clutches

The Fan Clutch is a fundamental part of your cooling system. Its drive shaft connects to the water pump. Then, the fan connects to the clutch housing. The fan clutch's task is to manage when the fan begins and off. It offers airflow when required. It also lowers drag on the engine when not needed - fan clutches.