Fan Clutch Recommendation

UKTJ

TJ Addict
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Dec 30, 2020
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Location
Hampshire, UK
I'm looking to do some preventative maintenance on my TJ's cooling system, one of the parts I am looking to replace is the fan clutch. I see in his excellent It Just Happened! thread @Irun purchased the Omix fan clutch, but that does not seem to be available from RockAuto at the moment. I wondered if there were any other brands of replacement fan clutch that are particularly well regarded / recommended?

As an aside, on RockAuto some of the fan clutches listed are stated to be "standard rotation" and others as "counter clockwise (reverse) rotation". But all of these are listed for my 2002 4.0l manual. What is the difference and can I only use one type?
 
Used a Hayden clutch fan 2 years ago that just failed last month. Replaced it with whatever I could get at the local Autozone to get me back up and running. Interestingly enough, the Hayden was made in Korea, the replacement here in the USA.
 
This afternoon I replaced the fan clutch on my TJ. As advised I fitted a Hayden 2771 as per above. I then refilled the cooling system with HOAT coolant and deionised water.

I decided to run the TJ for a bit to circulate the coolant and mix in with the water and to check all was well. It was far from well!

Here is the chronology of events as best as I can recall:
  1. I started the engine and the fan started up. I ran it with the radiator cap off, as I had read that waiting until the thermostat opened and the coolant started to circulate would help get air out of the system. Pretty quickly the level of coolant started to rise so I put the radiator cap on to stop more coolant overflowing.
  2. I then sat in the car to monitor the temp gauge. I had the heater turned to hot and the blower on full. The heater started to blow warm air, but then the air turned cold and no hot air was coming out.
  3. The temp gauge rose as far as about 40 degrees and then stopped rising.
  4. I decided to drive the TJ around the block to see if the temp would rise further and / or hot air would begin to be blown out again.
  5. Got about 100 yards and temp gauge very quickly jumped up to the 'normal' 12 o'clock position (marked on gauge as 100 degrees) but kept climbing beyond that.
  6. Turned around sharpish and got the TJ home and turned it off. I opened the bonnet to find the coolant reservoir full to brimming and the areas all around it wet and steaming, coolant had clearly been forced out of the overflow on the reservoir. I had filled the reservoir to half way between 'add' and 'full' when refilling the coolant system. Now the engine has cooled a little the coolant in the reservoir has been drawn back into the system and the reservoir is back to a little under the level I filled it to earlier.
  7. I tried to turn the fan, as my understanding is when up to operating temperature this should be hard to do if the fan clutch is working properly, but fan turned very easily.

Have I been sent a dud fan clutch? How would that cause the heater not to pump hot air? Air lock in system somewhere, could this explain all these symptoms?

I am due to go on a UK Jeep Owners Club event next weekend, so really hope I can get this sorted in the next few days. Any help much appreciated.
 
Most likely your coolant in the radiator never got hot enough to engage the fan.

You need to have the front of the jeep up higher to more easily get the air out. Park it pointing uphill, jack up the front, etc. Leave the rad cap off and let the coolant circulate and keep an eye on the level. Yes, it will burp some out as the air comes out, so be wary of that. You can blip the throttle to help as well. Once it settles down, cap the rad, fill the overflow to the full mark and drive it around. Once it cools check the overflow again, because it probably burped some more air out.

The loss of heat was due to air in the heater core.

The sudden changes on the temp gauge were due to steam in the system in the air pocket.

Once the coolant situation is taken care of you can check the fan operation. On a cold start, the fan will be fairly loud but will then quiet down. Then you should hear the fan pick back up when the hot air from the radiator causes it to engage.
 
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Most likely your coolant in the radiator never got hot enough to engage the fan.

You need to have the front of the jeep up higher to more easily get the air out. Park it pointing uphill, jack up the front, etc. Leave the rad cap off and let the coolant circulate and keep an eye on the level. Yes, it will burp some out as the air comes out, so be wary of that. You can blip the throttle to help as well. Once it settles down, cap the rad, fill the overflow to the full mark and drive it around. Once it cools check the overflow again, because it probably burped some more air out.

The loss of heat was due to air in the heater core.

The sudden changes on the temp gauge were due to steam in the system in the air pocket.

Once the coolant situation is taken care of you can check the fan operation. On a cold start, the fan will be fairly loud but will then quiet down. Then you should hear the fan pick back up when the hot air from the radiator causes it to engage.
That is really helpful, very many thanks.
 
Many thanks again @JKP, I seem to have resolved the issue. Before running the engine to operating temperature I ran the front up a couple of impromtu ramps to raise it up. I then ran it with the radiator cap off and heater on full until it was close to operating temperature, squeezing hoses occassionally. A fair bit of air came out along with some coolant. Had heat the hole time. Cap on and topped up the reservoir. Ran at idle for a bit and all seemed well, then took it out for about 20 minutes and temp stayed bang on 100 degrees.

Still found that fan clutch turned a bit easily once car was turned off and engine still at temp.
 
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