I just recently replaced my tractors belt drive fan for an electric fan and it yielded the opposite effect I was hoping for. Instead of it keeping the temps lower, it started overheating the engine. The fan I'm using is a Spal 30100435. It's a 10 inch fan, and fits pretty well in the radiator shroud. I did have to do a bit of jerry rigging to get it to fit, but nonetheless, it fits. I checked the thermostat and it opens like it should. The radiator is fine to my knowledge, as it was working fine before I changed the fan. It is still pulling air like the belt drive, and it is moving 10x as much air, but the engine is getting hotter than normal. Now, I know you're asking why would I change it if it wasn't broke. Well, I plan to add more power in the future by adding more fuel by advancing the timing on the pump, and also adding a turbo. I wanted cooling to be very efficient before messing with the engine. If anyone has any clue to why this is happening, any help would be super appreciated. I have asked many people what the problem could and they all were speechless.
Kubota tractor overheating when fan replaced to electric. (Kubota G1900S (D722))
- Thread starter jacoBiceps
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85Hokie
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" moving 10x as much air, "
Air like water needs to "pick up" the heat and move it. Same principle as taking the thermostat out of the cooling system - many people feel that taking the thermostat out HELPS cooling, but they find it does not.
While more air should pick up more heat - HOW the air is being moved may be your problem.
When you did " a bit of jerry rigging " - did you change any of the directional venting around the engine?
Air like water needs to "pick up" the heat and move it. Same principle as taking the thermostat out of the cooling system - many people feel that taking the thermostat out HELPS cooling, but they find it does not.
While more air should pick up more heat - HOW the air is being moved may be your problem.
When you did " a bit of jerry rigging " - did you change any of the directional venting around the engine?
GreensvilleJay
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This is another of the 'we need pictures' posts...
It could be that too much air is being moved which sounds 'wrong' but depending on HOW and WHERE the air flow happens ,can be why it's not working as expected.
It could be that too much air is being moved which sounds 'wrong' but depending on HOW and WHERE the air flow happens ,can be why it's not working as expected.
Here is a stupid question but... the belt is still there, running the water pump?
GreensvilleJay
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dang ,never thought of that but...
that fan needs 15 AMPS to run...+- 180 watts and according to online specs ,the dynamo only supplies 150 !!
THAT is a HUGE 'red flag'
The 802 CFM spec for the fan would be running 'flat out', so it'd be nice to see the actual voltage and current as it's being used. If less than 'spec', fan will run slower, far less CFM which could be the problem. I'd have to see the charts and graphs to work out the 'math'....
Bigger issue is with the fan taking ALL of the dynamo power, you can't have headlights on or fuel pump or anything else, at least not on paper. Since the engine runs, I doubt fan IS drawing 15 amps....
Now clever guys will have 2-3 sensors,computer, etc. to measure the engine's temperature and control the 'duty cycle' of the fan to properly get rid of the excess heat
that fan needs 15 AMPS to run...+- 180 watts and according to online specs ,the dynamo only supplies 150 !!
THAT is a HUGE 'red flag'
The 802 CFM spec for the fan would be running 'flat out', so it'd be nice to see the actual voltage and current as it's being used. If less than 'spec', fan will run slower, far less CFM which could be the problem. I'd have to see the charts and graphs to work out the 'math'....
Bigger issue is with the fan taking ALL of the dynamo power, you can't have headlights on or fuel pump or anything else, at least not on paper. Since the engine runs, I doubt fan IS drawing 15 amps....
Now clever guys will have 2-3 sensors,computer, etc. to measure the engine's temperature and control the 'duty cycle' of the fan to properly get rid of the excess heat
Belt driven fans move a lot more air.
I put an electric fan on my old diesel suburban, it would try to overheat in stop and go traffic but it was worth it for the +2mpg on the highway, since 80 to 90% of my miles were highway driving.
I put an electric fan on my old diesel suburban, it would try to overheat in stop and go traffic but it was worth it for the +2mpg on the highway, since 80 to 90% of my miles were highway driving.
ve9aa
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All or most of those electric fans are not what they are cracked up to be, at least in my experience. I built a 1948 Chrysler Winsor, and put a 350 hp small block in it. (I know, a small block Chevy in a Mopar but I could not get a 440 to fit). When the biggest baddest elec. fan did not cool, I did the extra work making a shroud and installing a belt fan. From then on it ran cool as a cucumber. Just my 2 cents..
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Well…so-far…. your modifications to OEM that was doing just-fine…are working really well…heh..?
(I don’t know how you measured the air movement or where you measured it…but I can tell you that a fan in conjunction with a shroud…. placement in-relationship to that shroud…even by as little as a fraction of an inch (within or outside the shroud) …can yield dramatic results….either positively or adversely.)
I didn't change the directional venting. By jerry rigging, I mean I had to bend the shroud to get the fan to fit.
I used a PWM fan speed controller to not have it run at full tilt all the time. Some people said it was moving "too much air".
How do you know this is true? How did you make that measurement?
If it is true, then others have pointed out that due to turbulance or whatever, the actual heat transfer to the air flow may be less due to increased flow. Try cutting back on the fan speed and see what happens.
But the first question remains. How do you know the amount of air is greater than the factory fan was pulling through the radiator to begin with?
I didn't really "measure" it. I could literally just feel that it was moving way more air. Probably not 10x exact, but I can definitely tell it was more than the belt drive fan. I put a PWM fan speed controller on it with no help.
I don't buy the theory that moving 'too much air' is the problem. How tight the fan fits in that shroud, well that is something that is worth looking at.
It is all kind of guess work as you haven't indicated you know how much air the oem fan moved or the amount the replacement is actually moving.
CFM meters are really pretty cheap.
It is all kind of guess work as you haven't indicated you know how much air the oem fan moved or the amount the replacement is actually moving.
CFM meters are really pretty cheap.
But what you are feeling with your hand might not represent what is flowing THRU the radiator fins. Could be turbulence or flow cause by air sucked in somehow in a place your hand is not at, that is causing you to assume that high flow is passing through the radiator.
Now it is a question of where you placed your hand. Was it on the side on the radiator opposite the fan? This would give you a better idea of air flow through the radiator.
Bottom line seems to be the OEM fan pulled the air through the radiator in a way that extracted more heat.
I can’t really help other than suggesting that you evaluate your assumptions and hopefully you will come up with the answer.
Also, it is likely the OEM fan was designed to pull maximum flow through the radiator, which presents a resistance to air flow. The specs of your electric fan may be based on an empty tube with the only resistance to air flow being the resistance to flow caused by the tube diameter and interface of the flowing air with the tube walls.
What is the wattage of the electric fan at max speed?
Which fan blade angles are more aggressive, belt driven or electric?
For the electric fan, is there any short circuited air flow; ie., through the fan, but not the radiator?
Point of reference for what it's worth: My Chevy Colorado 3.6L DI uses a ~800 watt fan with the alternator capacity to drive it. Diesels produce more heat under load.
Can you measure the electric fan RPM?
* I am assuming belt driven fan does not use a clutch so you can figure out it's RPM.
My take is the belt driven fan provides more airflow.
Which fan blade angles are more aggressive, belt driven or electric?
For the electric fan, is there any short circuited air flow; ie., through the fan, but not the radiator?
Point of reference for what it's worth: My Chevy Colorado 3.6L DI uses a ~800 watt fan with the alternator capacity to drive it. Diesels produce more heat under load.
Can you measure the electric fan RPM?
* I am assuming belt driven fan does not use a clutch so you can figure out it's RPM.
My take is the belt driven fan provides more airflow.