Cummins 330 Cooling Fan Question

[bigdomino]

I have the rear radiator in my Knight. Looks like 2 radiators, one on top of the other. I am wondering how the fan works? It seems to turn all the time. When the engine is stopped I try to move the fan and it won't move. I am guessing this radiator does NOT have a clutch. Does it run continuously?

How does it work whern the engine gets warm?

Steve__

[Our Time]

You are correct Steve, it is a direct drive fan that some say takes as much as 30 horsepower from the engine to run. They make a Horton fan kit that I had installed at the local Cummings shop. It is basically a electronic controlled fan clutch. It really cut the fan noise down and improved the mileage about 1 MPG and increased low end horsepower. Cost installed was $800 for our ISL.

[H. Miller]

Quote:

Originally Posted by bigdomino Does it run continuously? Steve__

Yes.
With 5 gallons of coolant, I am not sure that "engine cooling" is it's primary job. Our engine runs at 180 which says the thermostat is regulating engine temp.
That "other radiator" you mention is the charge air cooler (CAC) which cools the extremely hot air coming out of the turbo - all the time.
Not being a Diesel mechanic my guess is that continuous operation of the fan is as much or more for the CAC than the "water" cooling system. Besides, "no clutch" is cheaper than the hydraulic drive system used in some MH's to variabaly power the fan.