Are you going to replace a clutch or a fan of a cooling system? Here are some tips that could save you time and a second repair

August 11, 2026

Replacing a fan or a viscous clutch is a routine job in a workshop. However, many of the problems that arise after the repair are not caused by the replacement part itself, but by minor details in the assembly process that may go unnoticed. Here are a few points to bear in mind during the replacement process to ensure that the repair is carried out correctly and to prevent the vehicle from having to return to the workshop just a few days later.

Before you start, check the area

Not all trucks offer the same amount of workspace. On some models, it is sufficient to tilt the cab down to access the cooling system, whilst on others it will be necessary to disassemble protective covers, the fan deflector, cooling tubes or the radiator in order to remove the fan and the viscous clutch.

Taking a few minutes to work out the disassembly procedure and to assess the available space helps plan the work more effectively and avoids unnecessary disassembly.

If you can, work alongside another operator

The assembly comprising the fan and the viscous clutch can be bulky and difficult to handle, specially when space is limited.

Having a second operator on hand makes both the removal and the assembly easier, it reduces the risk of bumping other components, and it allows the assembly to be positioned with greater precision during installation.

Plan the disassembly before disconnecting anything

In some vehicles, it is easier to access the viscous clutch connector before removing the assembly, whilst in others it is better to wait until a later stage of the dismantling process.

Similarly, it is advisable to map out the cable route in advance to avoid unnecessary strain or damage to the connectors during the work.

If it doesn't seem to fit, don't force it into place

When the part is OEM-compatible, any difficulties found during assembly are usually due to the position of the assembly rather than the spare part itself.

Before applying force, it is advisable to check the alignment of the fixing points and reposition the fan and the clutch until the correct position is found.

Ensure the correct assembly

Before installing the clutch to the vehicle, it is necessary to check the clutch support and ensure that it is in good condition, paying particular attention to its bearings or silentblocks, if there are any.

Furthermore, during installation, it is necessary to ensure that both the clutch and the fan fit correctly into their housings right up to their final position. Clean the area beforehand to remove any residue that might prevent it from being fitted correctly.

Don't forget the deflector or housing

Once assembly is complete, make sure that the deflector or housing is correctly fitted and aligned.

Although it often goes unnoticed, its function is to direct the flow of air towards the radiator. Incorrect installation can reduce the efficiency of the cooling system, even if the fan is brand new.

Respect the tightening torque

The new viscous clutch or fan must be assembled in accordance with the specifications of the vehicle manufacturer.

Insufficient tightening may cause clearance or vibration during operation, whilst excessive torque may damage the screws and their sockets, compromising the integrity of certain components. 

Using a torque wrench and following the assembly procedure is the best way to avoid this sort of problem.

Take this opportunity to check the whole system

Once the system has been disassembled, you have access to components that are usually hidden from view.

Now is a good time to check the condition of the radiator, the belts, the sleeves, the water pump, the brackets and the viscous clutch bracket. Detecting a leak or wear in time can prevent the need for further repairs shortly afterwards.

Before handing over the vehicle, carry out the final checks

If during the repair the cooling circuit was opened, check the coolant level and carry out a full purge.

Before finishing the job, also check that the fan rotates freely, that there is no interference with the housing or any other component, and that all the wiring and fasteners have been fitted correctly.

The difference is usually in the little details

Most issues following a replacement are not caused by the part itself, but by little details in the fitting process. Planning the repair, checking the entire system and adhering to the manufacturer's specifications helps to reduce repair times and ensures that the cooling system returns to its expected performance.

At Cojali Parts, this philosophy also forms part of the development of our components. In addition to ensuring compatibility with the relevant application, our cooling system components undergo rigorous validation processes to ensure reliable and long-lasting performance.