I have a 2003 Disco. Looking to switch over to the Dorman 620-112 fan. But I am confused by the following threads which describe the use of either the Hayden 2781, 2791 or 2991 fan clutch:

https://landroverforums.com/forum/di...fitment-99274/
https://landroverforums.com/forum/di...al-fan-107134/
https://landroverforums.com/forum/di...-105042/page2/

If I interpret the info correctly from these threads, I conclude:

Hayden 2781 = standard duty fan hub
Hayden 2991 = severe duty fan hub (more noisy and may affect mpg)

I offroad ocassionally during the summer in the Pacific NW. The question is... do I go with the 2781 (standard duty) or 2991 (severe duty) with the Dorman 620-112 fan blade? Any thoughts or experiences to share?

Thanks in advance.

-----------------------------------------------------------------------------

Hayden 2781 Pic for reference:


Hayden 2991 Pic for reference:

 

What is your question?

 

It was in my first post:

The change will be for my 2003 Disco that has a different factory fan assembly than the pre-2002s. I offroad ocassionally during the summer in the Pacific NW. The question is... do I go with the 2781 or 2991 (when mating to the Dorman 620-112 fan blade)?

Thanks!

 

Either fan clutche will work with the Dorman fan you mentioned, they bolt up directly just like the OE clutch. You will need the hardware to attach the fan to the clutch.

I tried the severe duty based on feedback I got here. It was super loud and seemed to be spinning all the time. I found it really annoying and made it hard to diagnose running issues I was having at the time.

I went to the heavy duty and it was just right. More lockup than stock and kept the motor a little cooler, but not too much noise.

 

Arains44, thanks for the feedback!

 

Hey @acg start with heavy duty, the only time the severe duty helps is long very low rpm moves. On the Squamish hwy coming back from our last trip I never broke 194 in that miserable 5mph stretch, I am running the 2991.

It seems to lock less often than I would think but it works well on full lock - it does roar though on full lock

I did hit 199 trying to get to the Lions gate but I was basically stopped for 30 minutes, temps dropped to 186 inside 3 minutes of actually moving or bringing the revs up

 

I just put on the 2991. Temps are great, but I did a bunch of other changes at the same time. It roars like a jet engine.

 

Guys, thanks again for the input!

 

Update:

Temps went dwon significantly when I changed from the Hayden 2781 standard duty to the 2991 severe duty.

- Turner 4.6 (3 years old)
- Factory water pump (installed with the Turner engine)
- Nissen radiator (few weeks old)
- Idler, pulley, belt (one year old)
- Pentosin Pentofrost SF
- Extinct Inline thermostat

When I had the Hayden 2781, and even with a new Nissens radiator, I was seeing up to 215-deg F when going up gradients.

Now, with the Hayden 2991 @ 82-deg ambient and air-con turned on..... I am seeing 174 to 188-deg highway, 194-deg climbing. It did go up to 206-deg when I climbed to a top of a mountain and idled for a couple of mins, then started dropping quickly.0

 

I use the severe duty fan clutch with the Dorman fan on my 04 and it works great along with the OEM 180 degree t-stat.