New Fan Clutch

[Big T]

Had recent overheat incidents on my son's '94. Same trip, once while towing a camping trailer with a lot of windage and the other while not towing, but going up a long grade in the desert. I was not there, so this is second hand. He said that the EGT never got over 900, but the ECT reached 230 and he came out of the pedal and slowed to keep air going through the rad. Engine cooled fairly quickly both times. He said that he did not hear the fan coming on. This is a new occurrence with no prior overheats. As the radiator is new, the cooling stack is clean, plus they don't get that dirty in California.

Set-up:
2000 model HO Water Pump installed 2013 (30K miles)
DMAX fan installed 2013
AC Delco 195 T-stat installed 2013 (single T-Stat crossover)
AC Delco Fan Clutch (came off the '95 wreck, so probably close to 10 years old)
Radiator new one installed in the last year

Looking at fan clutches and trying to decide which one:
AC Delco 15461
Hayden 2840 Severe Duty
Hayden 2886
Kennedy?

 

[JayTheCPA]

Disclaimer up-front: am not convinced the best setup for our trucks is a thermal-viscous and the better solution is an electro-viscous. But recognize that we have not gotten to a good electro-viscous solution yet, so we are limited to the thermal spring.

With that lead-in . . .

When I did the P-400 conversion I used the AC Delco fan clutch (OE part) and it came out on the first time I pulled a serious load with it as I struggled to keep coolant temp down and rarely heard the fan engage.

Have the Hayden for the Kodiak (IIRC it is the 2886) which is definitely better than the AC Delco OE part. At the same time, it is just not cooling the way I want as it does engage, but still kicks in-and-out when pulling hard as the radiator is cool enough to let the clutch disengage and yet the coolant is still on the hot side. From what I had read, this is correctible by modifying the spring's lenght.


IIRC, WarWagon loves Kennedy's clutch as it engages early enough to keep ECT at or below 210F. Agree that the Kennedy design is definitely great and at the same time my read is that it is consuming more power than necessary (by way of more clutch lock-up) and more fuel (by keeping the motor cooler all of the time) on a regular basis; especially when the truck is also a daily driver. Not knocking, just saying.


Depending on pricing and free-time, might consider the Hayden (presuming it is still less expensive than Kennedy's) and modify the spring as appropriate / if necessary. Or just get Kennedy's and be done


One thing that does catch my attention is the comment regarding Cody's limiting EGT to 900F and reaching ECT 230F even when empty. For comparison, on long pulls with the RV (ex: 5+ miles of 5% - 6% grade), I currently keep the EGT's around 950F and the Hayden in turn is keeping ECT's in the low 220's. (And before anybody slams me about 220, I am personally comfortable with it given the military apparently lets the P-400 run to 240). While *empty* and the same grades with the AC Delco, the Burb's ECT's barely budged 210F. So am curious as to whether there are other issues effecting Cody's cooling stack in addition to just the fan clutch.

 

[Big T]

Disclaimer up-front: am not convinced the best setup for our trucks is a thermal-viscous and the better solution is an electro-viscous. But recognize that we have not gotten to a good electro-viscous solution yet, so we are limited to the thermal spring.

With that lead-in . . .

When I did the P-400 conversion I used the AC Delco fan clutch (OE part) and it came out on the first time I pulled a serious load with it as I struggled to keep coolant temp down and rarely heard the fan engage.

Have the Hayden for the Kodiak (IIRC it is the 2886) which is definitely better than the AC Delco OE part. At the same time, it is just not cooling the way I want as it does engage, but still kicks in-and-out when pulling hard as the radiator is cool enough to let the clutch disengage and yet the coolant is still on the hot side. From what I had read, this is correctible by modifying the spring's lenght.


IIRC, WarWagon loves Kennedy's clutch as it engages early enough to keep ECT at or below 210F. Agree that the Kennedy design is definitely great and at the same time my read is that it is consuming more power than necessary (by way of more clutch lock-up) and more fuel (by keeping the motor cooler all of the time) on a regular basis; especially when the truck is also a daily driver. Not knocking, just saying.


Depending on pricing and free-time, might consider the Hayden (presuming it is still less expensive than Kennedy's) and modify the spring as appropriate / if necessary. Or just get Kennedy's and be done


One thing that does catch my attention is the comment regarding Cody's limiting EGT to 900F and reaching ECT 230F even when empty. For comparison, on long pulls with the RV (ex: 5+ miles of 5% - 6% grade), I currently keep the EGT's around 950F and the Hayden in turn is keeping ECT's in the low 220's. (And before anybody slams me about 220, I am personally comfortable with it given the military apparently lets the P-400 run to 240). While *empty* and the same grades with the AC Delco, the Burb's ECT's barely budged 210F. So am curious as to whether there are other issues effecting Cody's cooling stack in addition to just the fan clutch.

Thanks Jay, this is good feedback. Given the purpose of the vehicle and the current oil price cycle, fuel economy is the least of our concerns. We simply want the best cooling solution as evidence by the mods or upgrades already installed (note; these were the first things we did when we got this truck). I checked and the Kennedy Fan Clutch is $175! The Hayden 2886 is $75. For $100, I can bend a spring.

I haven't driven the truck since this event, so all my info is via Colby and the EGT read could be inaccurate for all I know. I will inspect the truck tomorrow in the light of day. I am pretty confident the cooling stack is fine. I did inquire whether he had bled the air out of the system when he did the radiator. At the time we also redid the stab in heater line connector to the crossover as it had a small leak. Just don't remember whether he bled the coolant system of air, but he's been running it for at least 6 months since replacing the radiator, so this should have shown up earlier.

 

[Big T]

So pretty much settled on the Hayden, but which model? 2840 or 2886
Rockauto shows 2840 Severe Duty for the 2000 model K2500. When I look up the 2886, it does not indicate Severe Duty.

 

[JayTheCPA]

So pretty much settled on the Hayden, but which model? 2840 or 2886
Rockauto shows 2840 Severe Duty for the 2000 model K2500. When I look up the 2886, it does not indicate Severe Duty.

The 2840 also cross lists with the 1500 series too.


In looking over Rock Auto's descriptions, both the 2886 and 2840 show 'Severe Duty' in the description and share the 170F engagement temperature. Seem to recall that I decided on the 2886 given it was used in the Kodiak which implicitly got more heat load than the light truck service which a 2840 would see. Maybe this was a good decision, maybe not. But not worth swapping out unless AK figures out the electro-viscous setup; if he does, I am going EV

 

[WarWagon]

I have not had luck bending a spring. Found the fan clutch would stay on just about all the time. Just saying it's a narrow window to adjust and $100 of risk to engine from overheat and PIA to re-adjust isn't worth my time. I waste $100 on worse things. The sale price is nice as I have gladly paid more for the KD in the past.

Yes, the KD clutch locks in more and at full lockup. It does kick out despite rumors otherwise. I use it with a 195 T-stat and over the 180 the temps do spike higher. So 180 for towing and 195 for 'retirement' DD unloaded use. However it delivers cold AC faster over the Hayden. The Hayden comes on a little sooner then the OEM. Hands down the lower temp KD clutch delivers as promised.

CA is "summer" all the time with lots of all season bugs and blowing cotton/dirt from the farms. It is a bad assumption to think the stack stays clean.

 

[Big T]

I have not had luck bending a spring. Found the fan clutch would stay on just about all the time. Just saying it's a narrow window to adjust and $100 of risk to engine from overheat and PIA to re-adjust isn't worth my time. I waste $100 on worse things. The sale price is nice as I have gladly paid more for the KD in the past.

Yes, the KD clutch locks in more and at full lockup. It does kick out despite rumors otherwise. I use it with a 195 T-stat and over the 180 the temps do spike higher. So 180 for towing and 195 for 'retirement' DD unloaded use. However it delivers cold AC faster over the Hayden. The Hayden comes on a little sooner then the OEM. Hands down the lower temp KD clutch delivers as promised.

CA is "summer" all the time with lots of all season bugs and blowing cotton/dirt from the farms. It is a bad assumption to think the stack stays clean.

Joshua, this vehicle spends 90% of it's time in SoCal where it is 100% asphalt. It does see some offroading, but typically in desert or mountains. It see's virtually no travel in farm areas with blowing cotton/dirt. Based on my experience with my '99, I go years without having to clean the cooling stack.

 

[ak diesel driver]

FWIW Hayden has an e catalog. You can type in part number and look up all specs and what vehicles it came in

 

[WarWagon]

Joshua, this vehicle spends 90% of it's time in SoCal where it is 100% asphalt. It does see some offroading, but typically in desert or mountains. It see's virtually no travel in farm areas with blowing cotton/dirt. Based on my experience with my '99, I go years without having to clean the cooling stack.

It's just a "double check" type of advice as one is dealing with a cooling issue. My experience in the area is over the Grapevine and will of course differ. My stuff currently eats a lot of bugs year round to the point that single trips have resulted in the need to scrape them off the stack. One trip went through a bee swarm at 70 MPH and I was worried about the motorbike rider also zipping through it. Had to knock the dead bees out of the air filter the next day...

On the same hand nothing gets a free pass and this helps solve the problem the first time.

Other things come to mind like the older T-Stat sticking.

 

[FellowTraveler]

The medium truck clutch # 2886 has more than 100% increase in engagement area than the severe service unit.

The cooling stacks have massive air gaps at sides and top of radiator seal them and and the stack will function better. A fan clutch that cycles on/off/on/off at speed without really beating back the ECT's has an air gap problem.