Fan question

1Lawman · Oct 10, 2017

Why do manufacturers add a clutch to the fan on large tractors..The dealer tells me if I will let him lock out the clutch on the fan of my 5093E that my AC will cool better..What purpose is there in having a fan that goes on and off instead of just run all the time?

boomer1025 · Oct 10, 2017

A fan will rob horse power. Bigger the fan, more HP it takes to run it

1Lawman · Oct 10, 2017

boomer1025 said:
A fan will rob horse power. Bigger the fan, more HP it takes to run it

I assume that would also decrease fuel efficiency..

Zebrafive · Oct 11, 2017

1Lawman said:
I assume that would also decrease fuel efficiency..

Correct, it will decrease fuel efficiency (having fan clutch disabled), but it should less than the load the A/C adds when in use.

Spanner · Oct 11, 2017

The viscous fan is a critical component in the 'system' that keeps your engine at the optimum operating temperature . This is designed by intelligent engineers to maximise performance, power and fuel efficiency... and engine life. It engages/disengages at a pre-determined temp range. Alter that 'system' at your peril.

1Lawman · Oct 11, 2017

Spanner said:
The viscous fan is a critical component in the 'system' that keeps your engine at the optimum operating temperature . This is designed by intelligent engineers to maximise performance, power and fuel efficiency... and engine life. It engages/disengages at a pre-determined temp range. Alter that 'system' at your peril.

I think you helped me figure out the answer to my question. While I absolutely agree with your answer I also now recognize that intelligent engineers have to design a tractor that will not only work in mid August in Texas but also work in North Dakota in Jan..If designing a tractor only to be used in Texas I wonder if they would go to the added expense and complexity of using a viscous fan..I also wonder if they had Texas in mind when they put the AC evaporator and duct work in the roof..

Spanner · Oct 11, 2017

Dunno Lawman. But I did hear it snows in Texas too.

Tx Jim · Oct 12, 2017

The viscous drive fan has been mechanically locked on my '91 JD 4255 since about '95 or '96. My tractor would get too high operating temp while plowing in Texas heat. My dealer installed the fan lock up kit. I think the fuel saved by a viscous fan would be very minimal. I seriously doubt the fan clutch disengaged while engine was running in the Texas Summer heat. My 4255 uses 3.2 GPH of fuel pulling my JD 467 rd baler making 5.5 ft tall bales at close to maximum hyd pressure on forming belts. Engine has 11,500 hrs on original pistons/loners. For me I'd rather have the AC evaporator in roof than under the seat. I like where my AC vents are located in cab headliner on 4255 better than my Kubota M7040 in dash.

Tx Jim · Oct 12, 2017

Spanner said:
Dunno Lawman. But I did hear it snows in Texas too.

Not very often & thank God not very much nor does it stay on the ground very long. I hate snow!

1Lawman · Oct 12, 2017

Tx Jim said:
For me I'd rather have the AC evaporator in roof than under the seat. I like where my AC vents are located in cab headliner on 4255 better than my Kubota M7040 in dash.

That is interesting to me..You are the first one I've ever heard say that..You touched on something else I was also thinking about..On a hot day I would think the fan would likely run all the time anyway so I wonder if it would really make any difference..On the other hand I only use my tractor (5093E) in the summertime to cut my pasture with a 10' cutter so perhaps it is cutting on and off..