What controls the speed of a viscous cooling fan?
The engine cooling system uses On/Off viscous cooling fans that are applicable to wide range of engine loads with efficient energy consumptions. Depending on the temperature of the engine and the PWM signals, the power input and speed of the cooling fan automatically controlled by engine management system (EMS).
What controls the operation of a viscous engine fan?
The bimetal sensor governs the functioning of the viscous fan coupling. Primarily, there are two kinds of bimetal sensor systems: plate and coil. Both of them work under the same principle, as explained previously.
How does a viscous drive fan work?
How does a viscous fan work? The fan hub is a mechanical coupling that operates based on the ambient temperature. A bi-metallic strip on the outside of the hub heats and cools, and expands or contracts, which opens and closes a valve inside the viscous hub. As it warms up, the fan will kick in to keep the engine cool.
How do you test a viscous fan?
To confirm the diagnosis, start with this simple test: Spin the fan as hard as you can on an engine that has not been started that day. If the fan rotates more than five times, you can bet the clutch is bad. You should feel some resistance and the fan may spin up to three times, depending on the ambient temperature.
What is the purpose of a viscous cooling fan?
Viscous fan drives not only perform the essential cooling service of a fan drive, but also operate at variable speeds. This gives them a competitive advantage over fixed fan drives. Viscous fan drives engage and disengage less frequently than their fixed-speed counterparts, which: Reduces clutch wear.
How do I know if my viscous fan is bad?
Can a faulty viscous fan cause overheating?
Decrease in power, acceleration, and fuel efficiency A faulty fan clutch that leaves the fan permanently engaged will not only cause a noisy engine, but can also cause a decrease in performance. When it fails, the engine can be put at risk of serious damage due to overheating.
How to do a viscous fan drive test?
www.ets.borgwarner.com Subject: Viscous Fan Drive Test Procedure (Bi-Metal Drives Only) Diagnostic Procedure This test is most effective at an ambient air temperature of 80° (26.7°C) or higher. 1. Check the torque of fan blade fasteners. Refer to Table 2, Torque Chart. 2. Check the torque of fan drive-to-pulley, hub and bracket assembly fasteners.
How to adjust temperature on viscous fan clutch?
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When do you need a viscous fan coupling?
Viscous fan couplings are used on vehicles (cars and trucks) with inline engine positions, mainly rear wheel drives. These fans are needed at slow speeds and while idling. A faulty fan can cause an engine to overheat while idling or in heavy traffic, or poor mileage and loss of horse power.
Is the fan drive the same as the fan clutch?
The two terms “fan clutch” and “fan drive” are interchangeable. Although the fan clutch is driven by the engine, it is designed to stay “idle” in off mode and to turn on (with the engine as the primary force) as the engine temperature increases.