BJ42 Clutch Fan question

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Jan 4, 2007
Always on the Run
I have a 1983 BJ42 that did not come with a clutch type fan on the waterpump and wondering what the pros and cons are of it? I bought a new fan in which I asked for it to be a non clutch type and recieved the clutch type and wondering if I can just go with a clutch, if it will fit? Mine is an AUSSIE version LC so not sure if the CDN LC's came with them or not?

Canadian LC's came with clutch fans. I don't know exactly how they work, or if mine just doesn't work properly (turns all the time). I would assume it would help the diesel motor to warm up faster if the clutch allowed it to slip when cold.

I don't know the history of your truck or what you have on it currently, but if the engine is happy with the existing fan configuration, why change it?

Some "hard" mounted fans utilize flexible blades to pull air at lower RPM's and flatten out as the engine speed increases, reducing paratisitic drag on the motor. This system is an in-expensive alternative to the stock system that incorporates a viscous coupling (clutch) with a rigid fan.

If you are satisified with the performance (temp control, noise and fuel milaege) then changing the fan will be a spending excersise and probably not net any real tangible difference.

Yeah,I think this is how they came from AUS but I got the wrong fan and going to have to resend to Canada? So was just wondering if I can just buy a clutch and wondering what the Pros and Cons are? I heard alot of times the clutch doesnt even work or locks up?

I heard alot of times the clutch doesnt even work or locks up?

Yes, that describes a functioning viscous coupling fan clutch:

A) Cold or warm engine, the fluid in the clutch body is viscous and allows the fan to spin free, pulling less air through the radiator, making less noise and reducing paratisitic drag
B) Hot engine, the viscous fluid gels, creating a lock between the clutch and fan bodies. Now the fan is locked and turning at the water pump speed, creating more noise as the fan pulls air through the radiator.

When the stock system is functioning well, there is a noticable change in the sound level of the motor. You can hear the fan roar come in and out as the viscous coupling functions.

Note: The fan blade, viscous coupling and the thermostat operate in chorus with one another to regulate engine temp. If you want to install a clutch, replace the trio in order to have the best possible outcome for your investment.


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