Parts catalogs can be a mess. It's too bad because they can be pretty useful when you want to explore your options. That's how I found the 2791 in the first place, guess I got lucky because a mistake like some of these I would have just moved on without a second thought.
Should you get a heavy duty fan clutch?
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Parts catalogs can be a mess. It's too bad because they can be pretty useful when you want to explore your options. That's how I found the 2791 in the first place, guess I got lucky because a mistake like some of these I would have just moved on without a second thought.
Exactly! I do the same thing, researching and cross-referencing.
It's a little easier In today's digital age, I find the OEM part number then look those up across the vendors. (How I found the 2781.)
I was doing this very thing last night trying to find a copper crush washer for my VW oil drain plug and saw where some part number ending in "AA" was an acceptable substitution. I was like, "AA, is this a Chrysler part?" Sure enough, it was. I mean, it's a washer, but yeah.
I thought my fan clutch was bad but maybe not… I put my new one in (2791) and it was good for about a week and quieter down soon after I started driving. Then it started getting stuck at full speed like my other one did, even after driving for a few hours when it wasn’t hot out. Occasionally it will get quieter and stay that way for the duration of the drive, I noticed today that I revved my engine way up and it unstuck it.
Could I have some other problem causing this, like my engine running too hot? I keep an eye on the temp gauge and it never goes above just past the 210 line. I have noticed that my engine gets really hot after driving, like if I lift the hood up it’s too hot to touch and I drop it sometimes. But I’m not sure if all TJ’s are like that
Could I have some other problem causing this, like my engine running too hot? I keep an eye on the temp gauge and it never goes above just past the 210 line. I have noticed that my engine gets really hot after driving, like if I lift the hood up it’s too hot to touch and I drop it sometimes. But I’m not sure if all TJ’s are like that
Jcrubicon
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I just installed my 2791 today time will tell if it gets the job done any better. It barely fit with my cold case radiator the tolerances were so tight I had to wait for Both the radiator and engine to cool and contract to get it in the water pump 
Thanks for the info on this fan clutch maybe this pair with a fan like this derale 6 blade would cool better at idle?
It had the same bolt pattern and an additional blade like the old 7 blade fans?
https://www.summitracing.com/parts/...aYleHLJKR0ESwi-ECY5vgvTC49UcQ4WxoC_VQQAvD_BwE
Thanks for the info on this fan clutch maybe this pair with a fan like this derale 6 blade would cool better at idle?
It had the same bolt pattern and an additional blade like the old 7 blade fans?
https://www.summitracing.com/parts/...aYleHLJKR0ESwi-ECY5vgvTC49UcQ4WxoC_VQQAvD_BwE
I just installed my 2791 today time will tell if it gets the job done any better. It barely fit with my cold case radiator the tolerances were so tight I had to wait for Both the radiator and engine to cool and contract to get it in the water pump
Thanks for the info on this fan clutch maybe this pair with a fan like this derale 6 blade would cool better at idle?
It had the same bolt pattern and an additional blade like the old 7 blade fans?
https://www.summitracing.com/parts/...aYleHLJKR0ESwi-ECY5vgvTC49UcQ4WxoC_VQQAvD_BwE
@Davidtj installed the 6 blade.
https://wranglertjforum.com/threads/secondary-radiator-fan-electric.5573/post-261464
MountaineerTom
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I’m always looking for better A/C cooling here in the SC summers. That Derale fan is 18”. Is that the same size as the stock TJ fan? I’m not near my Jeep to check.
I just measured and to my eyes the stock fan is 18 inches.
@MountaineerTom have you noticed any difference with the 2791? I bought a 2771 to "downgrade" in hopes that it isn't so dang loud. I'll give it through next week to see if it makes any difference in engine temps, but it's still pretty loud. What's funny is it took to the same exact house in my neighborhood for it to quiet down as the 2791 did.
Some photos have been posted but I think this is the first time they've all been together for a group photo. Left to right, Hayden 2791, 2771, Delphi (OEM)
Clearly neither Hayden model is identical to the Mopar/Delphi. They probably cool just as well but from what I can tell the Mopar does a better job at freewheeling when it's not needed. Or maybe it started out like the Hayden and was just 16 years old.
Some photos have been posted but I think this is the first time they've all been together for a group photo. Left to right, Hayden 2791, 2771, Delphi (OEM)
Clearly neither Hayden model is identical to the Mopar/Delphi. They probably cool just as well but from what I can tell the Mopar does a better job at freewheeling when it's not needed. Or maybe it started out like the Hayden and was just 16 years old.
MountaineerTom
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I ended up taking it off some time back and going back to my 2771. I didn't see much difference in AC performance, but the extra noise ened up getting annoying.
I did install that Derale 18 inch 5 blade fan on the 2771 just the other day, but I haven't driven it much. It's loud too.
I ended up taking it off some time back and going back to my 2771. I didn't see much difference in AC performance, but the extra noise ened up getting annoying.
I did install that Derale 18 inch 5 blade fan on the 2771 just the other day, but I haven't driven it much. It's loud too.
I've got that derale saved in my Amazon list but it hasn't been hot enough this year to show any issues. Noise is an issue for me though. I hate feeling like every living thing in the area can hear me from a mile away and the first thing they hear (by a longshot) is the dang cooling fan. And it's even more maddening when there's no reason for it to even be engaged (like 40 degrees out with a thermostat stuck open, ect at 175 so there's no possible way the air coming off the radiator could be near the 170 it should require to engage the clutch)
@freedom_in_4low @MountaineerTom so let me get it straight - 2791 ends up making more noise than 2771, despite the original post claiming it’s quieter or should be theoretically (at least when it freewheels)?
Just want to make sure I understand, kind of hard to follow all the experiences in this thread. I thought the 2771 was the one people complained about noise with for years, if the 2791 is worse then that sucks.
Just want to make sure I understand, kind of hard to follow all the experiences in this thread. I thought the 2771 was the one people complained about noise with for years, if the 2791 is worse then that sucks.
The Hayden 2791 is identical eternally, to the new mopar clutch you get when you order a new oem unit. I have photos of that somewhere in this thread I think. My original clutch looked like yours on the left.
I'm only one drive into it but it seems to me like the 2771 is either the same, or maybe slightly quieter than the 2791. I'll keep updating as I get more run time on it.
My Mopar unit, which externally is identical to the 2791, is quieter than the 2791 and 2771 were with the units I tested.
Not overly so where I wouldn't just run the 2791 if price was a big concern for someone.
I would also add that I was originally having higher temp problems or temp creep at idle with the ac on. My heater core started leaking and about the same time the upper tank on my oem radiator cracked.
I replaced the heater core, water pump (MOPAR), radiator (mopar), motorad thermostat and fan clutch (mopar). Along with hoses and a preatone and then thermocure flush before new part installs. I no longer have temp creep issues and with humidity very high this year I have yet to see temps creep up like before.
None of the fan clutches in this thread will solve any overheating issues on their own IMO, unless it's clearly the fan clutch failing which is fairly easy to test.
I replaced the heater core, water pump (MOPAR), radiator (mopar), motorad thermostat and fan clutch (mopar). Along with hoses and a preatone and then thermocure flush before new part installs. I no longer have temp creep issues and with humidity very high this year I have yet to see temps creep up like before.
None of the fan clutches in this thread will solve any overheating issues on their own IMO, unless it's clearly the fan clutch failing which is fairly easy to test.
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MountaineerTom
LJ Enthusiast, Retired USAF Weapons Loader
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Sound wise, the 2791 was about the same as the 2771 on initial start-up for me. The whole point for me was trying to lower AC temps, so I was using it in hot months and with the AC on. It seemed to stay engaged all the time in that situation and got annoying. I'm sure the 2771 is engaged just as much but I guess I don't hear it.
The 2771 looks like the one that was on it when I bought it. I thought it was OEM, but maybe it wasn't.
I've had my Safari top here for a little while, but it's too damn hot and humid (and rainy) to enjoy driving it. I pulled the safari top off and plan to put the soft top back on tomorrow, so I'll be using the AC more and get a chance to see how the Derale fan does. @freedom_in_4low , just and a heads up, I did need to take a file and files down just a tiny bit on the clutch body, near the mounting holes, so the fan would slip down over it. A very minor amount.
The 2771 looks like the one that was on it when I bought it. I thought it was OEM, but maybe it wasn't.
I've had my Safari top here for a little while, but it's too damn hot and humid (and rainy) to enjoy driving it. I pulled the safari top off and plan to put the soft top back on tomorrow, so I'll be using the AC more and get a chance to see how the Derale fan does. @freedom_in_4low , just and a heads up, I did need to take a file and files down just a tiny bit on the clutch body, near the mounting holes, so the fan would slip down over it. A very minor amount.
Got some more time on it today. Keep in mind that right now I have unseasonably cool weather and a malfunctioning thermostat, so my coolant temp rarely gets above 190. It'll idle at 180 seemingly indefinitely, and this morning during the drive was never above 185. All this to say, the FSM specifies that the fan clutch should lock up with an air temp leaving the radiator of above 170 and I shouldn't be getting that.
Noise of course is subjective without expensive facilities and equipment that I don't have, and I'm aware of the fact that something can seem louder when I'm paying specific attention to it, but I'll say this: at worst, the 2771 could actually be louder at low temps and low speeds than the 2791 was, and at best, it's not significantly quieter.
I'm undecided for the moment but I may actually put my 17 year old Mopar clutch back on.
Noise of course is subjective without expensive facilities and equipment that I don't have, and I'm aware of the fact that something can seem louder when I'm paying specific attention to it, but I'll say this: at worst, the 2771 could actually be louder at low temps and low speeds than the 2791 was, and at best, it's not significantly quieter.
I'm undecided for the moment but I may actually put my 17 year old Mopar clutch back on.
I just did an hour drive with the old Mopar fan clutch and it was significantly and pleasantly quieter than either of the Hayden clutches. I idled in the driveway up to operating temp and took off, it unlocked by the time I reached the end of my driveway...which is about half a mile earlier than the Hayden fans unlock starting from cold. However, it also let the ECT get up to 212 with no signs of stopping while idling AC on in my driveway in 85F ambient, which might point to it being worn out.
I may just try another brand. I wish we knew a bit more about the current Mopar fan clutch, and whether it was completely identical to the Hayden 2791 or is it tuned differently.
I put an inch-lb beam type torque wrench on a 36mm socket and found that the 2771 would complete a revolution about 20% faster at 10 in-lbs than the 2791 did.
The most-bought fan clutch on Rock Auto listed for an 06 TJ is the US Motor Works 22160, which also appears to be sold under the Derale brand.
I may just try another brand. I wish we knew a bit more about the current Mopar fan clutch, and whether it was completely identical to the Hayden 2791 or is it tuned differently.
I put an inch-lb beam type torque wrench on a 36mm socket and found that the 2771 would complete a revolution about 20% faster at 10 in-lbs than the 2791 did.
The most-bought fan clutch on Rock Auto listed for an 06 TJ is the US Motor Works 22160, which also appears to be sold under the Derale brand.
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I have the older style fan clutch that bolts on with 4 nuts. I don’t have the extreme vs severe options but I’m thinking the US Motorworks version looks appealing. It has great reviews on Amazon or something last time I looked. I have had the Hayden 2771 or whatever the heavy duty use was and it is just too much. It DID look identical to my factory part but it did not perform the same. Probably different amounts of fluid inside if I had to guess.
I much prefer the 4 bolt fan clutch as it doesn't require a specialized tool to hold the water pump still. I put the Hayden on my 99 that was equivalent to the 2771 "heavy duty", and always noticed how much louder it was, but it didn't bother me quite as much on that one because it helped conceal an annoying lifter tap.
The USMW for the late model (1 large nut instead of 4 small) is on Amazon but shows out of stock so I ordered it from Rock Auto. I'm building quite a collection.