GM fan clutch install

Hardhatz · **Joined:** Mon Jul 21, 2014 7:58 pm **Posts:** 13

I just installed a radiator fan upgrade, among other things..
The fan I chose is a Dorman 620-602, which is made for various GM vans, pickups, and Hummers.
The clutch is from A 1 Auto 1aauto.com and is part# 1ARFC00002 and is presented as thermal.
I selected it based on glowing claims my the seller. (ebay)

The combination certainly moves air..
I'm pretty sure it would fly a Piper Cub.
On the downside, it runs full speed all the time.
I may have overdone it by choosing a "severe duty" rating.
I've just now sent the mfr a note about it, we'll see how they respond.

I find the plastic fan quieter.
But I really want that sucker PARKED when it's not necessary.
So, I'd like folks to share their brand-specific experience about this...

Thx!

WWDiesel · **Posted:** Wed Sep 18, 2019 1:32 am

Hardhatz wrote:

I just installed a radiator fan upgrade, among other things..
The fan I chose is a Dorman 620-602, which is made for various GM vans, pickups, and Hummers.
The clutch is from A 1 Auto 1aauto.com and is part# 1ARFC00002 and is presented as thermal.
I selected it based on glowing claims my the seller. (ebay)
The combination certainly moves air..
I'm pretty sure it would fly a Piper Cub.
On the downside, it runs full speed all the time.
I may have overdone it by choosing a "severe duty" rating.
I've just now sent the mfr a note about it, we'll see how they respond.
I find the plastic fan quieter.
But I really want that sucker PARKED when it's not necessary.
So, I'd like folks to share their brand-specific experience about this...
Thx!

I have the HAYDEN 2986 with the 11 blade GM plastic fan. Have not noticed any problems with it.
Yes it does move a lot of air, but that is why I installed it, for better cooling.
Not sure if your part no. crosses over to the 2986 as I could not find a cross reference for that brand
The 2986 is for Heavy Duty V8 Chevrolet/GMC trucks up to the 6.0 engine with towing package.
2986 Fan Clutch 07-99 GM Trucks; SUVs; Escalade; Hummer 6.0L; 5.7L; 5.3L; 4.8L; 4.3L

See this:> viewtopic.php?f=5&t=82941

Most complain about fan not moving enough air, and you are complaining about it moving too much air. :ROTFL:

GordnadoCRD · **Posted:** Wed Sep 18, 2019 4:58 pm

ALL thermostatic fan clutches in good working condition will pull SOME air regardless of temperature.
NO thermostatic fan clutch will lock up 100% under normal driving conditions, even at very high temperatures.
Depending on design, duty rating, temperature and RPM, all will range between roughly 20% and 90%.
My mods are listed below with brand and part#. I believe in this case, mine is virtually identical to WWDiesel's, and like him, I have had zero issues. Granted, I did not run with/without the fan on my dyno runs, but changing the alternator pulley made more of a noticeable difference than installing the GM 11 blade w/ severe duty Hayden fan clutch, regardless of the additional air pulled, and yes, that was a huge difference.
It's likely you are noticing it more with the vehicle stationary, than when it's moving down the road. Dynamic air load on the fan is far less than static.

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

WWDiesel wrote:

I have the HAYDEN 2986 with the 11 blade GM plastic fan. Have not noticed any problems with it.
Yes it does move a lot of air, but that is why I installed it, for better cooling.

Just mentioning it here because it got buried in the original thread, but it looks as though 2986 is no longer the current part number for the Hayden fan clutch; 2786 is.

And yep, this is a very worthwhile mod. We get about a 110°F temperature swing here throughout the year, and can confirm that it works exceptionally well in all seasons. I'd also recommend this mod if towing.

flash7210 · **Posted:** Wed Sep 18, 2019 7:25 pm

I’m running a fixed flex fan now.
Never have to worry about the function of a fan clutch

WWDiesel · **Posted:** Thu Sep 19, 2019 1:23 am

The 2986 is still listed on a few web sites, not sure what the story is on that part number. Would have to call Hayden to find out?
Amazon still lists them as available:> https://www.amazon.com/Hayden-Automotiv ... B000EQ7A9O

The 2986 is quite a bit more expensive than the 2786 at almost twice the cost. Not sure why so much for the 2986.

The problem that concerns me about the 2786 is it's overall height. All other specification numbers are identical.
The 2786 is 4.59" OH
The 2986 is 3.77" OH
This may present a clearance problem putting the taller fan clutch so close to the radiator stack?

They do list a 2780 and it has the exact same numbers as the 2986, OH are the same. 3.77
See this web page for a listing of all Hayden part numbers and their specifications:> http://pageturnpro2.com.s3-website-us-e ... -20-10.pdf

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

WWDiesel wrote:

The 2986 is still listed on a few web sites, not sure what the story is on that part number. Would have to call Hayden to find out?
Amazon still lists them as available:> https://www.amazon.com/Hayden-Automotiv ... B000EQ7A9O

The 2986 is quite a bit more expensive than the 2786 at almost twice the cost. Not sure why so much for the 2986.

The problem that concerns me about the 2786 is it's overall height. All other specification numbers are identical.
The 2786 is 4.59" OH
The 2986 is 3.77" OH
This may present a clearance problem putting the taller fan clutch so close to the radiator stack?

They do list a 2780 and it has the exact same numbers as the 2986, OH are the same. 3.77
See this web page for a listing of all Hayden part numbers and their specifications:> http://pageturnpro2.com.s3-website-us-e ... -20-10.pdf

Yeah, calling them to confirm would probably be a good idea. I seem to recall that when I did that (18 months or so ago), the person I spoke with wasn't really able to tell me what the differences between the 2986 and 2786 were, just that the 2786 replaced the 2986. It sounds like there may be some fairly significant ones, at least as far as installation in a CRD is concerned.

GordnadoCRD · **Posted:** Fri Sep 20, 2019 5:41 pm

HAYDEN

FAQ - Fan Clutches

How do I know if my fan clutch needs to be replaced?

Answer: A malfunctioning fan clutch can be hard to diagnose. Typically, the vehicle will NOT overheat unless operating in severe duty conditions. Since the vehicle is not overheating, the technician is not inclined to suspect an airflow problem. The challenge is to determine if the fan clutch is engaged and close to engine rpm. With an inexpensive infrared tachometer, a bad viscous fan clutch is much easier to diagnose by comparing fan speed to shaft speed. An engaged fan clutch will approximately read 80-90% of shaft speed. A disengaged fan clutch will approximately read 20-30% of shaft speed. A scan tool should also be used to check for codes that have been set by the EVC.

These are the most common symptoms of a failed fan clutch:

• Leaking fluid - Oily build up around the bearing or thermal spring
• Bad bearing - Seized, turns rough or has excessive play (more than 1/4" at fan tip)
• Worn thermal spring - Spring is loose

Some fan clutches will show no visible indication of a problem yet may still be faulty. The following may also indicate a faulty fan clutch:

• Fan spins excessively - Three or more times when hot engine is shut off
• Poor air conditioning - At low speed or excessive high side pressures
• Doesn't engage - Fan speed does not increase or "locks up" when the engine is hot
• Does not disengage - Fan clutch won't slow down when the engine is cold

What is the difference between a standard, heavy and severe duty fan clutch?

Answer: Each fan clutch type is designed to simulate the performance of the original equipment clutch that it replaces. All fan clutches are for specific applications and should be applied only on the vehicle for which they are cataloged. Use of the incorrect fan clutch may result in poor cooling, excessive noise, reduced fuel economy or fan clutch failure.

• Standard Duty Thermal: Turns the fan 50-60% of shaft speed when engaged. Used with fans with lighter pitch (1-1/2" of pitch). Flat plate impeller design with 30 sq. in. of working surface.

• Heavy-Duty Thermal: Turns the fan 80-90% of the shaft speed when engaged for increased cooling. Used with deeper pitch fans (2 1/2" of pitch). Land and groove design with 47 sq. in. of working area allows higher operating RPM's.

• Severe Duty Thermal: Turns the fan 80-90% of the shaft speed when engaged. Used with deeper pitch fans. (2- 1/2" of pitch). Land and groove design with 65 sq. in. of working area. Larger working surface provides cooler running and longer life expectancy.

At what temperatures do fan clutches engage?

Answer: Most fan clutches engage at about 170°F air temperature (about 180-190°F engine temperature). They reduce the temperature about 20°F before disengaging.

https://www.haydenauto.com/en/ecatalog?part=2786%20-%20Reverse%20Rotation%20Severe%20Duty%20Thermal%20Fan%20Clutch&type=p

Hardhatz · **Joined:** Mon Jul 21, 2014 7:58 pm **Posts:** 13

OK I now have the official reply from 1aauto.com and they weasled out, saying that because its on a different brand of engine they will not honor their "100% satisfaction, Lifetime" warranty.
No return.
No exchange.

Just my 2c worth. If you want to give them your money, go ahead.

:furious:

GM fan clutch install

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