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When the fan clutch fails ...

In my experience, it just made the fan not spin fast enough, period. When your engine is off, grab the fan and turn it by hand. There should be a bit of resistance. If it spins easily, it's shot. There is also a viscous coupler in the aluminum hub, when it goes bad there is usually evidence of gray fluid coming out of the sealed hub.
 
montanaman said:
When the fan clutch fails, does it ONLY make the engine run hotter?

Or ... does it make the fan spin not enough when it's hot, and too much when it's cold?
Click to expand...

Hallo. When the fan clutch was broken on my Jeep, the engine was running hot by idling and moving slow. On the highway , when moving fast, there was no problem. :laugh:


'92 XJ
 
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wim hoppenbrouwers said:
Hallo. When the fan cluth was broken on my Jeep, the engine was running hot by idling and moving slow. On the highway , when moving fast, there was no problem. :laugh:
Click to expand...

Generally speaking, if the XJ's cooling system is functioning properly, it will/should not over heat at highway speeds. At idle or stop and go traffic is a different matter.

Yes, if the fan clutch is bad, the XJ could over heat especially when going slow.
 
When cold, if you spin fan by hand as hard as you can, it should not spin more than 5 or 6 revolutions. When it gets hot, it should get noisier as it starts to flow more air. If you stop the motor when hot, the fan should have significantly more resistance.
 
Fan clutches can fail:

1. Failing to spin enough (60-70% of shaft speed) = engine overheat in low air flow conditions.

2. Locked up (100% of shaft speed) = excessive fan noise, engine drag and poor MPG.

3. Bearing failure (wobbling) = damage to water pump bearings and possible impact with radiator.
 
joe_peters said:
Fan clutches can fail:

1. Failing to spin enough (60-70% of shaft speed) = engine overheat in low air flow conditions.

2. Locked up (100% of shaft speed) = excessive fan noise, engine drag and poor MPG.

3. Bearing failure (wobbling) = damage to water pump bearings and possible impact with radiator.
Click to expand...

Hallo. Not the same pulley imo. " damage to water pump bearings ?" :yap:

'92 XJ
 
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Meh, His post is essentually right, except for the waterpump bit.

-Ron

edit: 5-90, I've had one fail as locked up. It does exactly what he stated.
 
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I don't think I've ever seen a fan clutch lock up, but I wouldn't rule it out (I've seen plenty of them start losing fluid, so I'd think it possible.)

The ones I've seen fail have failed because the viscous fluid in them loses viscosity, and they allow too much "slip." Best test? WITH THE ENGINE HOT, right after you shut down, either watch the fan stop (it should happen fairly quickly - not more than two or three full turns) or let it come to a stop and spin it by hand - there should be fairly significant resistance when it's hot (you can hasten the process on a cold engine by heating it with a hairdryer on HIGH for about three or four minutes.)

From what I've gathered over the last few years, the service life of a fan clutch on the XJ runs about five years or so - write the date on the next one you replace, and start looking for it to fail in about four. It's a "maintenance part" with a fairly long maintenance interval - which is why I suggest writing the date on the thing.
 
Zuki-Ron said:
Meh, His post is essentually right, except for the waterpump bit.

-Ron

edit: 5-90, I've had one fail as locked up. It does exactly what he stated.
Click to expand...

I'm not saying it can't happen - I just haven't seen it. It would probably happen when the clutch loses nearly all (or just all) of the viscous fluid that makes it work - and the impellers would lock up.

I just don't let them go that long:)
 
So, what is the best place for a new fan clutch (and possibly fan) flex-a-lite or OEM?
 
wim hoppenbrouwers said:
Hallo. Not the same pulley imo. " damage to water pump bearings ?" :yap:

'92 XJ
Click to expand...

I hate to break it to you all, but yes, there are bearings pressed into the water pump housing.

I guess you thought that was just an empty hole bored through the housing and the shaft, which is steel, is just kind enough not to wear the housing out?

Cut a water pump open, educate yourselves.
 
mine didn't show any problems before it fell apart one day driving home from work. Of course, it was in April. I unbolted the fan clutch and drove home. Drove it two more days until I had all of the parts I needed. the electric fan kicked in when needed and the motor never overheated. I got the clutch from Quadratec and the fan and new shroud from the local dealership.

you should be able to find the clutch at most good parts stores, but the fan will be harder to find.
 
joe_peters said:
I hate to break it to you all, but yes, there are bearings pressed into the water pump housing.

I guess you thought that was just an empty hole bored through the housing and the shaft, which is steel, is just kind enough not to wear the housing out?

Cut a water pump open, educate yourselves.
Click to expand...

There are certainly bearings in a water pump - no-one is arguing with you there.

However, the XJ/MJ with the 242ci six doesn't mount the fan clutch to the water pump (like everyone else does,) the fan clutch and fan run on an idler pully under the A/C compressor, and on that same bracket. That's why losing the fan clutch on an XJ won't necessarily kill the water pump - because the fan assembly would go unbalanced and end up killing the idler (and maybe dinging up the AC compressor clutch as well.)

They couldn't mount the fan to the water pump if they put in an e-fan - because there wouldn't be room. So, they mounted the fan off centre and added the secondary.

That's where everyone else is coming from - the fan clutch and fan aren't mounted to the water pump (like everyone is used to.)
 
5-90 said:
There are certainly bearings in a water pump - no-one is arguing with you there.

However, the XJ/MJ with the 242ci six doesn't mount the fan clutch to the water pump (like everyone else does,) the fan clutch and fan run on an idler pully under the A/C compressor, and on that same bracket. That's why losing the fan clutch on an XJ won't necessarily kill the water pump - because the fan assembly would go unbalanced and end up killing the idler (and maybe dinging up the AC compressor clutch as well.)

They couldn't mount the fan to the water pump if they put in an e-fan - because there wouldn't be room. So, they mounted the fan off centre and added the secondary.

That's where everyone else is coming from - the fan clutch and fan aren't mounted to the water pump (like everyone is used to.)
Click to expand...

Just another symptom of my Oldsheimer's.
 
whatevah said:
mine didn't show any problems before it fell apart one day driving home from work. Of course, it was in April. I unbolted the fan clutch and drove home. Drove it two more days until I had all of the parts I needed. the electric fan kicked in when needed and the motor never overheated. I got the clutch from Quadratec and the fan and new shroud from the local dealership.

you should be able to find the clutch at most good parts stores, but the fan will be harder to find.
Click to expand...
This the one you got? http://www.quadratec.com/products/51202_07.htm
 
Johnnie Walker said:
This the one you got? http://www.quadratec.com/products/51202_07.htm
Click to expand...
yup, that's it. I just checked the receipt to be sure. bought it on 4/18/07.

main.php
 
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