How does a manual clutch fan work?
Most fan clutches are filled with a silicone-based oil. The oil is held in an internal reservoir when the fan is disengaged. To engage the fan, internal valves open and allow the fluid to fill the working area of the clutch. This creates friction between the drive plate and the housing, causing the fan to spin.
What is the difference between a heavy duty and severe duty fan clutch?
A Heavy Duty fan clutch will lock up 70 to 80 percent when engaged. A Severe Duty fan clutch will lock up 80 to 90 percent when engaged. Fan blades with a pitch of under 2 ½”, require a Standard Duty fan clutch. Blades with a pitch of over 2 ½” can use either Heavy Duty or Severe Duty clutches.
Are radiator fans supposed to spin?
A mechanical fan WILL spin as long as the engine is running, but it will only ‘lock up’ when needed. Secondly, why does my radiator fan turn on and off? To avoid a further rise of temperature, the fan induces air flow. The fan turning on is normal and a consequence of the hot coolant, not a cause.
When do you disengage the thermal fan clutch?
When cooling is not needed, the fan clutch is disengaged. As the pulley spins, typically driven by the belt, the fan is driven at a minimal speed (usually 10 to 20 percent) reducing drag on the engine. As the coolant heats up, the air passing through the radiator increases in temperature.
What happens to the fan clutch at high speeds?
At low and idling speeds, the clutch allows the fan blade to turn at almost a 1:1 ratio. At high speeds, the silicone fluid within in the clutch will lose its ability to transfer the energy from the shaft to the fan clutch body (and therefore, the fan) and the fan is then allowed to almost free-wheel, removing its load from the engine.
Do you need a solenoid valve for a fan clutch?
Freon Pressure Switch, and N.C. Solenoid Valve are the only controls absolutely necessary for Fan Clutch operation. The N.C. Manual Switch, Air Pressure Switch, and Indicator Light are all optional controls and may be left out of the circuit.
What are the different types of fan clutches?
Types of Fan Clutches. The main types are non-thermal, thermal, and electronic — all of which use a silicone fluid to engage and disengage your fan. Non-thermal clutches operate solely based on the shaft speed of the water pump. At low and idling speeds, the clutch allows the fan blade to turn at almost a 1:1 ratio.