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Old 05-30-2013, 07:06 AM   #1
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Fan Clutch Question

Ok this is probably a really dumb question and I am ok with a little ribbing so no worries.

But I have read all of the posts on overheating issues which is what my YJ is having.

Some posts mention that you should not be able to turn the fan more than a little bit 1/3 of a rotation or something like that.

Now I have a serpentine belt and I can spin my fan all day long with out it binding so is the ability to turn it only if you have a v-belt?

Here is an even simpler question exactly what the heck does the clutch do?
I mean my fan runs all the time as long as the engine is running the fan is moving so what gives here? What is it that I am missing?

Thanks

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Old 05-30-2013, 07:59 AM   #2
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The clutch is disengaged until the engine gets hot. The fan spins yes but only because its hooked to the engine but it does not spin at full RPMs. Once the clutch gets to the correct temp it engages and then the fan starts to rotate at the same RPM as the engine. You should feel a little resistance (engine off) while you spin the fan. Also a good indicator that the clutch is bad will be if the fan has too much side to side wobble.

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Old 05-30-2013, 09:46 AM   #3
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If you are moving at 55mph for example does it run cool? Then, get hot when you are at a stand still? If so, then it could be your fan or possibly clogs in the radiator. Think about it, when you drive you create wind. If your fan is failing, you'll still have 55mph winds keeping the engine cool.

Now, if your tooling down the road at 55mph and she starts to run hot, something else is wrong such as the water pump, low coolent, radiator, etc...
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Old 05-30-2013, 01:28 PM   #4
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fan clutch

Chris,

Thanks for the information the jeep is not able to go on the road at the moment. No rear axle I am upgrading the rear end to a DANA 44 and have not had a new drive shaft made let alone installed. SYE is in Rear end is in. No Drive shaft so I can not go 55 but at an idle in the drive way it will get hot enough to boil the coolant. I had an issue with the wiring getting melted to one of the coolant temp sensors the forward one to be exact but I have fixed that. It has a new water pump, new radiator, new thermostat, new thermostat housing and has been flushed with just a hose while I had the thermostat out and the water pump off. Was not all that dirty till I got to the overflow reservoir that was nasty but I cleaned it out as well.

I have a new front coolant temp sensor that I will install tonight but as of lunch when I fixed the melted wiring issue it still overheats.

Also if the cooling system is completely drained how much coolant should it take to fill the entire system 2 gallons or more?

Also if I have air in the system how do I get it out.

Oh the hoses are all new except the one coming out of the heater coil going into the coolant manifold in the back near the temp sensor that is in the back.
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Old 05-30-2013, 03:20 PM   #5
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Chris,

Thanks for the information the jeep is not able to go on the road at the moment. No rear axle I am upgrading the rear end to a DANA 44 and have not had a new drive shaft made let alone installed. SYE is in Rear end is in. No Drive shaft so I can not go 55 but at an idle in the drive way it will get hot enough to boil the coolant. I had an issue with the wiring getting melted to one of the coolant temp sensors the forward one to be exact but I have fixed that. It has a new water pump, new radiator, new thermostat, new thermostat housing and has been flushed with just a hose while I had the thermostat out and the water pump off. Was not all that dirty till I got to the overflow reservoir that was nasty but I cleaned it out as well.

I have a new front coolant temp sensor that I will install tonight but as of lunch when I fixed the melted wiring issue it still overheats.

Also if the cooling system is completely drained how much coolant should it take to fill the entire system 2 gallons or more?

Also if I have air in the system how do I get it out.

Oh the hoses are all new except the one coming out of the heater coil going into the coolant manifold in the back near the temp sensor that is in the back.
Check the fan clutch front and back see if it looks like a oil leak
The fan clutch it's got a small amount of oil when the oil gets hot because of the engine running the fan clutch gets harder to turn to cool down the engine
If the fan clutch spins freely when the engine is cool down fan clutch might be bad
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Old 05-31-2013, 07:46 AM   #6
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Fan Clutch

Ok update for the forum.

So I installed the front coolant sensor and no change still overheats.
I will install a new clutch fan tonight when the part comes in this afternoon.

On the positive side I did get the rear brakes connected up and bled so I now have rear disc brakes. Pretty good for a jeep that can not drive out of the drive way I can sure stop it if it rolls!

Thanks for all the help guys and gals

Chief
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Old 05-31-2013, 08:07 AM   #7
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Ok update for the forum.

So I installed the front coolant sensor and no change still overheats.
I will install a new clutch fan tonight when the part comes in this afternoon.

On the positive side I did get the rear brakes connected up and bled so I now have rear disc brakes. Pretty good for a jeep that can not drive out of the drive way I can sure stop it if it rolls!

Thanks for all the help guys and gals

Chief
Hopefully the fan clutch fixes your problem
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Old 05-31-2013, 09:46 AM   #8
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How To Tell If A Fan Clutch Is Defective

1) Check for oil streaks (or dust collected on oil streaks) on the fan clutch. It's a sure sign that the internal fluid that provides the clutch action is leaking.


2) Check for a worn bearing. Grasp the fan blade on either end, with the engine off, and check for lateral movement. If there's more than 1/4" of side-to-side movement, the bearing is worn and the unit needs replacement.


3) Check for proper fan clutch operation. First, run the engine until operating temperature is reached. Next, with the engine off, give the fan blade a gentle spin. If it rotates more than twice, the clutch is worn and needs replacing. If fan rotation is rough or noisy, or the fan fails to turn, the unit is worn out and needs replacement.
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Old 05-31-2013, 10:21 AM   #9
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fan clutch

Thanks FAB

I will give that a try at lunch.

Chief
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Old 06-03-2013, 07:51 AM   #10
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fan clutch question

Ok update for the forum

Checked the fan clutch it is fine. I am starting to think I may have a blown head gasket I have replaced all the simple easy to fix things.

I do not have water in the oil and there is none coming out the tailpipe nor is there a smell of coolant when running the engine short of having a clog in the cooling system for sitting for over a year with out running by the previous owner I am at a loss. I have heard there is a test you can do to the radiator fluid to see if exhaust gases are getting in the coolant system any one have experience with this?
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Old 06-03-2013, 09:55 AM   #11
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Ok update for the forum

Checked the fan clutch it is fine. I am starting to think I may have a blown head gasket I have replaced all the simple easy to fix things.

I do not have water in the oil and there is none coming out the tailpipe nor is there a smell of coolant when running the engine short of having a clog in the cooling system for sitting for over a year with out running by the previous owner I am at a loss. I have heard there is a test you can do to the radiator fluid to see if exhaust gases are getting in the coolant system any one have experience with this?
Do a compression test to each cylinder
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Old 06-03-2013, 10:00 AM   #12
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Hope hygiene wasn't asked already (looked and didn't see it asked) but are you going off the gauge or it boiling over? If it is not boiling over then your gauge may be bad or the wiring going to it, since you said that it had burnt before. Chase the wire as far as you can see if there is not another problem in he wiring.
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Old 06-03-2013, 10:29 AM   #13
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No it boils and steams!

As soon as the thermostat opens the fluid explodes out of the radiator cap with it off!
With radiator cap on it bubbles out of the reservoir.

Everything I have read and talked with people suggests blown head gasket I was just hoping for the best that it was a thermostat or water pump issue.

was going to pressure test next to confirm but I have to check with my neighbor to see if he has the tester equip or take it some where and have it tested.

Thanks for all the help guys and gals
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Old 06-10-2013, 09:39 AM   #14
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fan clutch question

Turns out the culprit was the fan it was a clockwise rotation fan and not a counterclockwise rotation fan.

For those that do not know if you have a serpentine belt you need a reverse rotation fan.

If you have a v-belt style then you need standard rotation fan.

An easy test to do is take a towel or rag or something light and place it in front of the grill of the fan sucks the towel into the grill your fan is running correctly still could be the clutch but at least you know the fan is moving air in the right direction. Live and learn I guess with older vehicles.

Still runs a little hot in my opinion but that again is only at an idle
I also burped it several times and got air out in fact I had to jack the front end up on the jack pretty high to get all the air out all tricks I learned from the neighbor mechanic.

For those that do not know what I mean by burped it I started the Jeep let it warm up and took the radiator cap off and let the air bubbles gurgle out of the cap it actually worked very well and when I mean warm up I do not mean 210 degrees I mean started the jeep took the cap off. You can also watch the coolant flow this way as well.

Safety note Be careful the coolant gets HOT!

Overall I think I got if fixed will not know for sure till I get a rear drive shaft made and can take it on the road.
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Old 06-10-2013, 04:06 PM   #15
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I'm glad you got it sorted! Just out of curiosity is the clutch the same for clockwise and counter?
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Old 06-10-2013, 06:44 PM   #16
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No the clutch is not the same for clockwise as counter clockwise
should have mentioned that in the previous thread

sorry

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