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How do I know if my fan clutch is bad?

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Old 09-25-2009, 04:31 PM   #1
The Old Pit Pony
 
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How do I know if my fan clutch is bad?

Hi All
I have a 2001 S10 4.3L V6 Automatic with A/C. I swapped out the DexCool for Prestone yellow about 3 weeks ago, my temp guage came up to just under 100 Celcius, about 195 Farenheit and the upper rad hose got real hot, I figured all was good. Now the weather is colder and the temp guage doesn't rise above the one quarter notch mark, the upper rad hose never gets hot, there is only minimal heat in the cabin heater.

I notice the fan is spinning now at all times, from as soon as the engine is started, even if stone cold. With the engine off and cold, I can spin the fan with only minimal resistance, with engine off and now warmed up as much as it will warm, the fan clutch still spins with only minimal resistance.

I understand there is also a temperature sensor on the left head area, this can apparently run my engine in a "rich" mode.

So how do I tell if my fan clutch is my problem or the temp sensor is causing the engine to run in a "cold mode"?

Thanks
Old 09-25-2009, 05:18 PM   #2
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Re: How do I know if my fan clutch is bad?

Do you have sufficient fluid in system?

The thermostat could have died ... would keep engine from warming up ... you can use temp "sticks" to test ... I have a cheap Sears multimeter with a temp probe which works well ... perhaps you have something similar?

Just about any thermometer that you can couple to thermostat housing will work. I've attached service manual extract for the sticks.

Regarding the fan ... I've attached extract from service manual with a few hints for testing the clutch.

Last edited by far2grumpy; 12-27-2010 at 06:38 PM.
Old 09-25-2009, 08:20 PM   #3
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Re: How do I know if my fan clutch is bad?

Hi Far2Grumpy

I'll try to get some of those temp sticks tomorrow. Meantime, I wonder if the fan might simply be spinning because it is attached to the water pump , even if the clutch is not "engaged". Could be that is what I am seeing, it simply spinning free kind of thing.

I have an new AC Delco 195 degree thermostat, I think I'll get that installed tomorrow. I would try it myself but I know the last time I did this, like 30 years ago, I broke the white metal housing, afraid I'll tighten it too much, I know my manual says 18 lbs torque but I guess I am just gun-shy of those housings!

Thanks for your prompt reply!
Old 09-25-2009, 09:22 PM   #4
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Re: How do I know if my fan clutch is bad?

I have a 04 S-10 Crewcab with 4.3 and my fan sounds like a 747 at take-off thrust for a few minutes after a first start of the day. I've noticed neighbors looking to see if the street cleaner is on the street when I back out and move off.

I would say ugly things about the viscous coupling used in the fan clutch but I've owned four AWD Subaru's through the years ... they use similar methods to transfer power to rear wheels ... so I suppose you could say the technology is proven.

My project for the weekend is to replace the mechanical clutch with an e-fan set-up. I've had the parts stacked up for weeks so its probably my last garage project before winter strikes Iowa. I won't be discarding any of the existing stuff ... just in case the e-fan disappoints.

I wish you success with your cooling (heating) problem.
Old 09-25-2009, 09:29 PM   #5
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Re: How do I know if my fan clutch is bad?

Quote: Originally Posted by far2grumpy
I have a 04 S-10 Crewcab with 4.3 and my fan sounds like a 747 at take-off thrust for a few minutes after a first start of the day. I've noticed neighbors looking to see if the street cleaner is on the street when I back out and move off.

I would say ugly things about the viscous coupling used in the fan clutch but I've owned four AWD Subaru's through the years ... they use similar methods to transfer power to rear wheels ... so I suppose you could say the technology is proven.

My project for the weekend is to replace the mechanical clutch with an e-fan set-up. I've had the parts stacked up for weeks so its probably my last garage project before winter strikes Iowa. I won't be discarding any of the existing stuff ... just in case the e-fan disappoints.

I wish you success with your cooling (heating) problem.


You should be quite happy with e fan. Ive done 4 of them in s10's always using camaro fans and shrouds. Just did one last week.
Old 09-25-2009, 09:44 PM   #6
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Re: How do I know if my fan clutch is bad?

my 91 s10 also sounds like a 747 when taking off from the fan, otherwise cools great
Old 09-25-2009, 10:00 PM   #7
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Re: How do I know if my fan clutch is bad?

Quote: Originally Posted by 992drjimmy
You should be quite happy with e fan. Ive done 4 of them in s10's always using camaro fans and shrouds. Just did one last week.
Does the Camaro fan have a dual speed motor?

I wound up with a 93 Taurus fan (spent too much time researching on internet) ... it does move some air in my bench setup but I've yet to determine how it'll matches up with radiator.
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