A quick update with the 2991 fan clutch...simply awesome. 3 days of offroading. Climbed to 2000-metres. Hardly broke a sweat. 174F to 179F pretty much all day. Went up to 188F after a long climb. Then settled down quickly to 179F. The fan hub does sound like a jet turbine engine when under load though. But no worries at my end to have the cooling peace of mind.

 

Man I put the 2991 on and only lasted one leg to work. I swapped back to stock before driving home lol. So freaking loud and was a noticeable loss of power with the stronger clutch that I'm not sure I was willing to live with. I may throw it back on and consider running it during the summer bc I'm sure its toasty on these long mountain passes.

 

Thats funny. I never really think of the 2991 as "loud". Coupled with the Dorman fan it works really well and I get 15 mpg with mostly highway driving.

 

I have had the inline thermostat and Hayden 2781 for the last couple of years and always thought my temps ran a bit high...ranging from 186 - 218F depending on ambient temperature.

After installing the Hayden 2991 fan clutch last week I have made several test runs in 100F+ temps with AC running and on average the coolant temp seems to run ~198F and the max coolant temp is now 205F while climbing steep grade up to 9000ft elevation.

In hindsight it makes a lot of sense that the severe duty fan clutch is a better match for my high desert environment.

 

More positive confirmation on the 2991 after 4 hard days of off-roading. 85 to 90-plus F ambient. Many long steep, hairpine winding (slow) climbs up and down the canyons.

Last year... the Hayden 2781 could not keep up and temps went up to 221-F.

A few days ago, the Hayden 2991 only hit 204-F after the same long climb. I am also seeing great 174 to 179-F temps when traversing slowly on flat rocky tracks.

All this with A/C on running at 64 to 68-F in the cabin.

 

Glad that the set up worked for you and thank you for the detailed feedback.

 

Asking for Follow up on this set up. Just installed it a week ago. Posted it on a D2 FB site and got a reply to remove it or the blade will grenade. True?

 

Uh, first of all, there are a lot of nutjobs in the FB DII groups.

If the fan blade grenades, it's not because of the fan clutch. Did you inspect the fan blade for cracks when you installed the new fan clutch?

And finally, you refer to "... this set up." Which fan clutch did you install? I've had the 2991 in my truck for four years and all is well.

 

@Zonk872 yea the guy who posted that is an idiot. While non metal fans can and do fail short of a bad fan out of the box most failures are either age or object strike damage. The dorman fan being whitish is very easy to check for cracks, and you should check it after setting up camp if you have done any deep water crossings, or trail with a lot of small branches type pop up as you go over them. It literally takes 5 minutes.

 

I installed the Hayden 2991 with the Dorman 620-112 Fan.

Yes, checked condition of fan

Thanks for following up!