Hydraulic engine fan

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afchap

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Dec 19, 2008
Posts
1,279
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...East TX, or on the road...
I have an 02 Spartan Mountain Master chassis with a Cummins ISC engine. It has a hydraulic engine cooling fan.
It is not thermostat controlled.  Does this fan turn at a specified RPM after initial startup or does it change with engine RPM? I know it spins up when I initially accelerate from a stop but at say 1500 engine RPM is the hydraulic cooling fan turning slower than it would be at 2500 engine rpm?
 
It's driven by a hydraulic pump rather than direct off the crankshaft, so I doubt is it is directly controlled by engine rpms. Whether it varies much with rpms, I cannot say.  You would have to ask Spartan, since they designed the cooling system (Cummins won't have a clue what Spartan did).

The drawback of this type of cooling system is that the horsepower load on the engine is fairly constant, so hurts fuel economy when cooling demand is low.  I think the hydraulic drive is better than a direct belt drive fan, though.  The more sophisticated systems have a  variable speed hydraulic fan. Later model years probably had that type, but 20 years ago nobody worried too much about diesel fuel economy.
 
Probably has a fan controller. Some are electronic. Others use a wax device. Call Spartan. No
 
Bet you have a fan controller that varies speed based on engine or sensor input.  My 2000 Country Coach with hydraulic fan has a controller with 3 sensors for input; charge air cooler temp, coolant temp, and OTR air conditioning.  Later models were controlled by the engine computer.
 
You have the same set up I have on my American Trad. the fan RPM is controlled by the variable pressure of the pump, in my case it's the power steering pump. Some of the later ones had a temp controller that engaged at a preset temp.>>>Dan
 
I installed a repair kit in mine 9 years ago for $90.00,, been great since.>>>Dan
Hey I'm new to the forum. I am having a small leak around the shaft and seal of my side cooling fan motor. I'm curious as to what kit you bought for 90 bucks that fixed your problem? Your issue, part number, Company you bought it from and even an update on how your fix is doing? Thanks and I look forward to interacting with you and viewing information on this forum. Mark
 
Actually. it is a pump on of two that are usually on that shaft (the other one pumps water) It's also a motor... Hard to explain but "Hydrostatic" means some fluid likely a liquid is pumped and that fluid in turns powers the fan's hydraulic motor Torque converter is another device that kind of works the same way only... much, bigger.
 
On his 8.3 will be a gear drive pump installed on the curb side of the engine behind the high pressure fuel pump.. It serves the coolant fan and the power steering system,, the fan "motor" has no clutch or sensors attached,, only an in line and out line.. Mine rev's with the change in engine RPM..>>>Dan ( I also have the same Mountain Master chassis.)
 
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