Frequently Asked Questions

A non-thermal fan clutch is nothing more than a thermal fan clutch always partly engaged. It provides adequate cooling when needed, however, it does not save you money by disengaging (operating at a lower RPM) when additional cooling is not needed.

The engagement temperature varies model to model. Most automotive clutches engage between 70°C and 80°C air temperature at the face of the clutch.

These are the most common symptoms of a failed fan clutch:

  • Engine overheating – with engine hot and ignition off, spin fan 1-11/2 revolutions indicates a worn clutch.
  • Excessive Fan Clutch play – push the tip of the fan blade in and out. Any visible looseness in the clutch shaft means the bearing is worn.
  • Greasy build up – Oily streaks radiating outward from the hub shaft or fluid leaking at centre of thermostat spring.
  • Bad bearing - Seized, turns rough or has excessive play (more than 1/4" at fan tip).
  • Freezing up – If the fan blade cannot be rotated by hand, or if hand rotation causes a harsh rumbling, the fan clutch bearing has failed.
  • Shaft vibration – The fan clutch is mounted on the water pump between the water pump shaft and the fan. Any vibration can mean a worn bearing in the water pump o fan clutch. Since the fan clutch and water pump have about the same life span, it makes sense to replace both at the same time.
  • Worn thermal spring - Spring is loose.

Some fan clutches will show no visible indication of a problem yet may still be faulty. The following may also indicate a faulty fan clutch:

  • Fan spins excessively - Three or more times when hot engine is shut off.
  • Poor air conditioning - At low speedor excessive high side pressures.
  • Doesn't engage - Fan speed does not increase or "lock up" when the engine is hot.
  • Does not disengage - Fan clutch won't slow down when the engine is cold.

Note; The fan clutch should be checked for possible replacement when a replacement water pump is being installed.

A thermal clutch fan operates using silicon fluid as a viscous coupling medium. When the clutch is cool and disengaged, most of the silicon fluid is stored in the reservoir allowing your fan clutch to slip relative to your water pump shaft thereby spinning at a lower RPM than the water pump. This saves you money because the horsepower from your engine is not wasted driving a clutch fan when it's not needed. As your engine heats up, the thermal spring on the front of the clutch expands, which opens a valve allowing the silicon fluid to drive your clutch at an increased RPM. This provides more air flow through your radiator, preventing your car from overheating.

A non-thermal fan clutch is nothing more than a thermal fan clutch always partly engaged. It provides adequate cooling when needed, however, it does not save you money by disengaging (operating at a lower RPM) when additional cooling is not needed.

The engagement temperature varies model to model. Most automotive clutches engage between 70°C and 80°C air temperature at the face of the clutch.

These are the most common symptoms of a failed fan clutch:

  • Engine overheating – with engine hot and ignition off, spin fan 1-11/2 revolutions indicates a worn clutch.
  • Excessive Fan Clutch play – push the tip of the fan blade in and out. Any visible looseness in the clutch shaft means the bearing is worn.
  • Greasy build up – Oily streaks radiating outward from the hub shaft or fluid leaking at centre of thermostat spring.
  • Bad bearing - Seized, turns rough or has excessive play (more than 1/4" at fan tip).
  • Freezing up – If the fan blade cannot be rotated by hand, or if hand rotation causes a harsh rumbling, the fan clutch bearing has failed.
  • Shaft vibration – The fan clutch is mounted on the water pump between the water pump shaft and the fan. Any vibration can mean a worn bearing in the water pump o fan clutch. Since the fan clutch and water pump have about the same life span, it makes sense to replace both at the same time.
  • Worn thermal spring - Spring is loose.

Some fan clutches will show no visible indication of a problem yet may still be faulty. The following may also indicate a faulty fan clutch:

  • Fan spins excessively - Three or more times when hot engine is shut off.
  • Poor air conditioning - At low speedor excessive high side pressures.
  • Doesn't engage - Fan speed does not increase or "lock up" when the engine is hot.
  • Does not disengage - Fan clutch won't slow down when the engine is cold.

Note; The fan clutch should be checked for possible replacement when a replacement water pump is being installed.

Davies Craig Thermatic Fans are available in two packaging options:

1.KIT - includes: Fan Assembly, Wiring Loom, Relay, Mounting Hardware, Comprehensive DYI Fitting Instruction Sheet for automotive application

2. SHORT - includes: Fan Assembly (motor, fan blade, shroud), Installation Instructions

*Davies Craig offer Kit and Short Thermatic Fans in 12 & 24 volt versions across our range.

A Davies Craig Thermatic Fan ‘Short’ is suitable for both air conditioning/refrigeration condenser and radiator cooling. A Thermatic Fan is the most important component on any cooling/refrigeration system. Thermatic Fans provide; strong, consistent & high capacity air flow, increased air conditioning/refrigeration performance, fully reversible blades and polarity for bi-directional air flow, additional mounting flexibility, low profile & high performance.

No, Davies, Craig Thermal Switch (Part No. 0401,0402 & 0404) must be mounted in the engine compartment near the radiator. The EWP/FAN Digital Controller (Part No. 8020) should be mounted inside the vehicle cabin to access the controls and feedback information away from direct sunlight and should not be exposed to excessive heat.

Yes. Davies, Craig electric fans work equally as well in either position. The instructions show how to install the fan blade and reverse the wiring to accomplish this. The fan blade must always turn in the direction of the arrow on the fan hub. Also always follow the instruction “This side must face front of vehicle”.

The "pump too fast lose less heat” notion is very popular and many experienced mechanics are very attached to it but – it is a fallacy. Davies Craig has been carrying out research and development for over a decade on a number of projects and has never been able to pump genuine liquid coolant faster and lose less heat. In all car engines, when the mechanical pump reaches cavitation speed, coolant turns into a gaseous state which is compressible,(liquid is not) and the real flow rate of liquid coolant drops even though the mechanical pump has a higher rpm, and so heat loss drops. The engine temp then rises. And it only seems like the flow rate is too fast, and the coolant is spending too little time in the radiator to lose its heat etc. etc..

A non-thermal fan clutch is nothing more than a thermal fan clutch always partly engaged. It provides adequate cooling when needed, however, it does not save you money by disengaging (operating at a lower RPM) when additional cooling is not needed.

The engagement temperature varies model to model. Most automotive clutches engage between 70°C and 80°C air temperature at the face of the clutch.

These are the most common symptoms of a failed fan clutch:

  • Engine overheating – with engine hot and ignition off, spin fan 1-11/2 revolutions indicates a worn clutch.
  • Excessive Fan Clutch play – push the tip of the fan blade in and out. Any visible looseness in the clutch shaft means the bearing is worn.
  • Greasy build up – Oily streaks radiating outward from the hub shaft or fluid leaking at centre of thermostat spring.
  • Bad bearing - Seized, turns rough or has excessive play (more than 1/4" at fan tip).
  • Freezing up – If the fan blade cannot be rotated by hand, or if hand rotation causes a harsh rumbling, the fan clutch bearing has failed.
  • Shaft vibration – The fan clutch is mounted on the water pump between the water pump shaft and the fan. Any vibration can mean a worn bearing in the water pump o fan clutch. Since the fan clutch and water pump have about the same life span, it makes sense to replace both at the same time.
  • Worn thermal spring - Spring is loose.

Some fan clutches will show no visible indication of a problem yet may still be faulty. The following may also indicate a faulty fan clutch:

  • Fan spins excessively - Three or more times when hot engine is shut off.
  • Poor air conditioning - At low speedor excessive high side pressures.
  • Doesn't engage - Fan speed does not increase or "lock up" when the engine is hot.
  • Does not disengage - Fan clutch won't slow down when the engine is cold.

Note; The fan clutch should be checked for possible replacement when a replacement water pump is being installed.

Each fan clutch type is designed to simulate the performance of the original equipment clutch that it replaces. All fan clutches are for specific applications and should be applied only on the application for which they are catalogued. Standard Duty Thermal Turns the fan 50-60% of shaft speed when engaged. Used with fans with lighter pitch fans. (1-1/2' of pitch) Flat plate impeller design with 30sq.in. of working area. Heavy Duty Thermal Turns the fan 80-90% of the shaft speed when engaged for increased cooling. Used with deeper pitch fans (2 1/2" of pitch). Land and groove design with 47sq.in. of working area allows higher operating RPM. Severe Duty Thermal Turns the fan 80-90% of the shaft speed when engaged. Used with deeper pitch fans. (2-1/2" of pitch). Land and groove design with 65 sq.in. of working area. Larger working surface provides cooler running and longer life expectancy.

A non-thermal fan clutch is nothing more than a thermal fan clutch always partly engaged. It provides adequate cooling when needed, however, it does not save you money by disengaging (operating at a lower RPM) when additional cooling is not needed.

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