Should you get a heavy duty fan clutch?

[TexasTJ2004]

This is what I'm seeing today with my setup. Good news I don't have a radiator leak. It was the upper hose lose which was been corrected. Still monitoring this though. I am not losing coolant, at least not enough to notice yet. Belt squeals on command at and above 3k in 1st and 2nd gear. I'm going to try a new belt. I'll save the new radiator I purchased for now. I don't mud this jeep but I'll give the radiator a cleaning too. System was flushed last year with new heater hoses.

It is 100 here today and I got to 240 after a drive a up to Ace for an errand. It hit 240 in the parking lot after about 10 minutes of sitting once I arrived with the ac on max. All with the 2791 installed.

This what that looks like on my gauge at 242. It's hot today

View attachment 345525

sitting in the jeep typing this and it's back up.to 242 degrees. I'm going to clean this radiator for now and see what does.

There is very mixed info it seems on the acceptable temp range for these. Some day 210 to 240 is normal. Some say above 230 is not normal. I'm over it for now and

Especially if @MountaineerTom is seeing similar results from a refreshes system. Meanwhile @rasband sitting nice with a very fresh system.

I am in Houston, and was getting the same numbers as you get with AC on while parking, even worth when very slowly moving in long drive through.
I am replacing a radiator (to Mopar one), thermostat (Mopar) and a fan clutch (Hayden 2771).
Also, going through a coolant flushes (BlueDevil and then Thermocure).

 

[Inline.TJ]

No. Convert to electric.

 

[Apparition]

No. Convert to electric.

Which one?

 

[Inline.TJ]

Which one?

FK45 Fan Controller + 1995 Taurus Fan (three wire)

 

[Apparition]

FK45 Fan Controller + 1995 Taurus Fan (three wire)

You have one? I’ve not read of any working that well.

 

[Inline.TJ]

You have one? I’ve not read of any working that well.

Yessir. Been running it for 9 months now. Works like a charm.

 

[freedom_in_4low]

I've been talking to my buddy who was an engineer for jeep truck back when the LJ was designed. His work on the LJ was in suspension but he worked on HVAC and cooling system on other models. He said continuous 220 is about the highest he'd want to see, with brief spikes to 230-235 being ok as long as it wasn't continuous, with the additional caveat that your pressure cap needs to be healthy.

 

[MountaineerTom]

I've been talking to my buddy who was an engineer for jeep truck back when the LJ was designed. His work on the LJ was in suspension but he worked on HVAC and cooling system on other models. He said continuous 220 is about the highest he'd want to see, with brief spikes to 230-235 being ok as long as it wasn't continuous, with the additional caveat that your pressure cap needs to be healthy.

You put a hand throttle in, correct? You should be able to bump the idle up a little and get it to drop a decent amount while parked. When mine got up in the high 230's, I pressed the throttle slightly just to get a few hundred more RPM's and the temps started dropping. Once actually driving away, temps dropped pretty quicky.

 

[freedom_in_4low]

You put a hand throttle in, correct? You should be able to bump the idle up a little and get it to drop a decent amount while parked. When mine got up in the high 230's, I pressed the throttle slightly just to get a few hundred more RPM's and the temps started dropping. Once actually driving away, temps dropped pretty quicky.

Yeah, and that works really well. I only have to bump it up to 1200 or so and the temp drops like a stone. Since my fan clutch looks like the factory one that was superceded in 2009, I'm probably going to swap it out with the 2791 and see what happens.

My main concern is I get up into the low 220s on the highway. I should have plenty of airflow at that point. .

 

[Longwhitejeep]

You put a hand throttle in, correct? You should be able to bump the idle up a little and get it to drop a decent amount while parked. When mine got up in the high 230's, I pressed the throttle slightly just to get a few hundred more RPM's and the temps started dropping. Once actually driving away, temps dropped pretty quicky.

Yeah same. Mine dropped very quickly once you blip the throttle. Side note, new gates belt, no more belt squeak. Old gates belt will be a spare I guess.

 

[freedom_in_4low]

Interesting observations today. Temp was mid 90's outside, A/C on max the whole day. Ran some errands in town, then headed out to some of the dirt/sand roads out in the country near my house. Hayden 2791 fan clutch installed. Around town and stop and go traffic temps fluctuate between 203* -210* on the Dash Command App. Seemed pretty normal. Once done with my errands, I headed out to the dirt roads. Slow driving between 5 - 15 MPH, stopping every now and then to watch snakes and deer. While sitting still, temps creeped up to 217*-223* and quickly dropped down to low 200's after moving again. Spent about 1-1/2 hours out doing this.

Went to a restaurant to get something to eat. About 10 cars ahead of me so I spent about 15 minutes in line. A/C still on max, temp on Dash Command App got up to 239*. After getting my food and heading back home, temps dropped again to low 200's while driving in the 2 miles back to my house.

Decided to put the 2771 back on and see what it did. Swapped them out, let the jeep sit and idle for 30 minutes. It ran for 20 minutes before it reached 225* and by 30 minutes it was 237*. Again, temps dropped to low 220's pretty soon after driving. When the Dash Command App showed 239* with the 2791 clutch and 237 with the 2771, the temp gauge on the dash showed about the same, just starting to get into the zero of the 210 lettering. I've seen the instrument cluster gauge get up into that range before with the 2771 was on but never realized it was high 230's because I've never used the Dash Command App when sitting and idling for that long, I guess.

@freedom_in_4low , @Longwhitejeep and @pagrey , I'd be interested in hearing what temps you show if you have an OBDII reader that shows temps when sitting idling for 20 - 30 minutes.

Dash Command App screenshot and pic of the instrument cluster with the 2791 clutch installed.
View attachment 345185

View attachment 345186

I just met a guy to sell some axle shafts I had laying around. I sat idling in a parking lot with the AC on max and 101 outside while I waited and chatted with the guy. When I got back in it was 231.8. I gave it some hand throttle and it pulled down to 212 in what seemed like 60-90 seconds. I took off and it was down to 204 before I got on the highway. It climbed back up to 216 within 2 miles where I took my exit again.

From there it was some low speed stop and go stuff, but no idling and no speeds above 45. Temp floated as low as 197 and as high as 212. At one point I stopped at the grocery store for milk and when I got back in it was 238 and idled rough but temp dropped and idle smoothed out before I was out of the parking lot. I heard the fan moving when I was off idle so other than the poor temperature control and advanced age I'd have no reason to suspect the fan clutch, but I'm gonna try to get it changed out this week and see what happens.

 

[Longwhitejeep]

Interesting notes for today. I swapped the Mopar clutch because I had it and just couldn't send it back in the name of science for the forum .

What I noticed was similar performance but the Mopar seemed to let temps.climb quicker to 210 but hold them like the 2791. The Mopar 68064765AA clutch was noticeably quieter though and start up fan noise was shorter in duration.

Max temp at idle the Mopar got to was 233 with ac max before I had to get back to work. It's 93 degrees today.

It almost seemed like the Mopar had a few stages of activation. Around 217 it engage drop to 210 or so but I couldn't hear it like the Hayden. Even when engaging my clutch for a neutral rev like I did with the Hayden to test noise.

My take away from this is the 2791 works well but maybe a bit noisier though not unnecessarily so. The Mopar 68064765AA clutch was quieter and seemed to engage less or just when needed. If I was budget conscious 2791 all day, if I wanted the best quiet operation Mopar.

I am keeping the Mopar mainly because I can't return it now.

Fwiw you can buy about 3 Hayden for one Mopar.

 

[Cheetokps]

Interesting notes for today. I swapped the Mopar clutch because I had it and just couldn't send it back in the name of science for the forum .

What I noticed was similar performance but the Mopar seemed to let temps.climb quicker to 210 but hold them like the 2791. The Mopar 68064765AA clutch was noticeably quieter though and start up fan noise was shorter in duration.

Max temp at idle the Mopar got to was 233 with ac max before I had to get back to work. It's 93 degrees today.

It almost seemed like the Mopar had a few stages of activation. Around 217 it engage drop to 210 or so but I couldn't hear it like the Hayden. Even when engaging my clutch for a neutral rev like I did with the Hayden to test noise.

My take away from this is the 2791 works well but maybe a bit noisier though not unnecessarily so. The Mopar 68064765AA clutch was quieter and seemed to engage less or just when needed. If I was budget conscious 2791 all day, if I wanted the best quiet operation Mopar.

I am keeping the Mopar mainly because I can't return it now.

Fwiw you can buy about 3 Hayden for one Mopar.

Debating if I should get the mopar if it’s really that much quieter. I was going to try the 2791 since my 2771 went bad, but noise is a big factor for me so maybe it’s worth it

 

[Longwhitejeep]

Debating if I should get the mopar if it’s really that much quieter. I was going to try the 2791 since my 2771 went bad, but noise is a big factor for me so maybe it’s worth it

When Temps climbed past 220 at idle it sounds like the Hayden did when you rev it. Drops temps.like the Hayden the difference was less noise and drag noticed under that 220 degree mark.

I would be happy with either but I understand the desire for less noise.

 

[pagrey]

Debating if I should get the mopar if it’s really that much quieter. I was going to try the 2791 since my 2771 went bad, but noise is a big factor for me so maybe it’s worth it

Mopar and the Hayden 2971 extreme duty will make less noise overall, the 2771 is louder normally because when it isn't engaged it is spinning the fan slightly faster. New Mopar should be very similar to the Hayden 2971 but really they are all going to be very similar and better than an old worn out clutch.

These smaller differences in running temps between Jeeps are much more likely to be from some other thing. Nothing wrong with tracking temps and sharing notes but I don't think it has much to do with the clutch. I think most people that are this far into it should just read the difference between the two maybe from the first post and pick which one they think suits their needs better.

 

[pagrey]

Mopar 68064765AA clutch came in and looks exactly like the 2791 fan clutch.

The whole point of this thread is exactly this, the frequently recommended 2771 isn't what the factory intended and your pictures show that better than pretty much anything else. Thanks for posting them if I didn't say it before.

(put a link in the original post to your pictures)

 

[freedom_in_4low]

The whole point of this thread is exactly this, the frequently recommended 2771 isn't what the factory intended and your pictures show that better than pretty much anything else. Thanks for posting them if I didn't say it before.

(put a link in the original post to your pictures)

I think you're giving Mopar a lot of credit. The factory didn't intend the 2791 either because the Mopar clutch we're getting now wasn't installed on any TJ when it left the factory, per the parts manual which lists a different pn. If you look at the 2791 on rockauto you'll see a mile long list of OEM part numbers it replaces. Odds are that at some point after the end of TJ production they saw an opportunity to consolidate half a dozen or more parts into one and just picked an existing aftermarket part that met the speed ratio and temperature requirements they needed and slapped a Mopar label on it.

 

[pagrey]

I think you're giving Mopar a lot of credit. The factory didn't intend the 2791 either because the Mopar clutch we're getting now wasn't installed on any TJ when it left the factory, per the parts manual which lists a different pn. If you look at the 2791 on rockauto you'll see a mile long list of OEM part numbers it replaces. Odds are that at some point after the end of TJ production they saw an opportunity to consolidate half a dozen or more parts into one and just picked an existing aftermarket part that met the speed ratio and temperature requirements they needed and slapped a Mopar label on it.

What point are you trying to make? Could you post a picture of the Mopar clutch that looks like a 2771?

 

[freedom_in_4low]

What point are you trying to make? Could you post a picture of the Mopar clutch that looks like a 2771?

52027883AC. It doesn't look exactly like the 2771, though it looks more like it than it does 2791. My point though isn't that one is right and one is wrong...it's that the original is NLA and we get a few choices of which none are exactly what the engineers intended, but most are probably close enough to work, and not different enough for most people to notice.

Btw, Crown sells one under the 52027883 part number that looks exactly like the one currently installed on my LJ and the above photo, but I bought the 2791 because I didn't find any reviews of the crown on here.

 

[freedom_in_4low]

took the LJ out to the new house to visit with the plumbers doing rough-in. It was about 100 with a dew point in the 60s. I ran out there with no AC, and ran AC on max coming back. On the 45-55mph stretches I never saw more than 203 without AC, and at 75mph on the interstate it leveled about 210. Having the AC seemed to have about a +10 impact on my ECT. This is obviously an extreme scenario because in real life I should be running cooled and dehumidified recirculated cabin air, not running no windows in 100 with humidity.