• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Thermostatic Fan Clutch

NVW

NVW

Well-Known Member
Messages
9,890
Reaction score
5,000
Location
Castor, AB.
What is your preference, AC Delco or Hayden? This will be for a 98 nine blade steel fan.
 
I run the Hayden medium truck one as it has 100%+ more engagement & holding area over the severe duty one w/steel fan. I had more than a few occasions where the severe duty failed when needed in the mountains and desert sw the medium truck unit solved that problem.
 
Thanks WW, for the 3 weeks above 80* up here the Hayden will likely be good enough.:rolleyes:

My original one off the 95 never let me down, I have the 98 fan and clutch on it now and the clutch isn't the best.
 
I ran Heath's Hayden fan; better engagement, torque transfer, worked just fine with my 94 towing big weight.
 
Thanks Jim.

My clutch is at the post office, will install and give my opinion of it.
 
Hayden # 2886 med truck fan clutch just threads on to pump & has 112% more viscous clutch engage area than severe duty 6.5td fan clutch has and just installed and has run w/o any issues for a few years now.
 
JayTheCPA said:
Part number? :)

And did you just drop-it-in and run, or need to adjust the coil?




Out of curiosity, what brand / model is Kennedy starting with?
Click to expand...

I don't recall. Email him and ask him and I am sure he would say. He orders them in batches with 15 degrees lower than the stock set point. Used to have this info along with the fan torque curve on the site, but, not there anymore. Note all fan clutches loose 200 RPM per year and best replaced at 5 years old. I am just happy that the system works well with what I throw at it even in the mountains where there is snow I need the fan. The turbo change reduced cooling needs as well.
 
For those of you using kenndys clutch is it the bolt on or the threaded on? I tried two of the bolt on ones and didn't have good success with it. I'm thinking the threaded one is the better one from all the post I've read so far
 
spollock818 said:
For those of you using kenndys clutch is it the bolt on or the threaded on? I tried two of the bolt on ones and didn't have good success with it. I'm thinking the threaded one is the better one from all the post I've read so far
Click to expand...

Bolt on. He just started offering the thread on version in the past few years. The cooling system needs major work for results. Clean stack, HO water pump, clean internal radiator... I find the GM turbo is a major restriction and adds lots of cooling system load vs. a larger turbo. I ran a 180 T stat and recommend that for towing, but, recently went to 195 for the unloaded use I give it now.

Curious to the issues you had?
 
I've had my rad rodded and cleaned out my cooling stack many times. Running the metal 9 blade fan and still was running 210+ unloaded up steep grades without the clutch kicking in. I also have a CKO HX40Wi on it too. Tried all stats combo, have a HO pump and dual stat set up. No air in system and run about 40% coolant. DE exhaust and K47 air box. The only thing I can think of is that my condensor is restricting flow, but I've cleaned that so many times. With air, degreaser, and soft pressure washing. I can see the water come through but I'm at a loss now
 
Have you removed the oil coolers and cleaned the mat that builds up behind them? Any bent fins on the condenser?

Verified the temps with an IR temp gun as the gauge/sender could be going bad?

Dual T-Stats need a bypass restrictor. Single T-stat have the restrictor as part of the thermostat. Some aftermarket T-Stats don't have this required bypass blocker.
 
Have the restrictor and have taken both coolers off and pressured washed them clean multiple times. My fins look good on the condensor and radiator too. It was rodded and hot tanked at a shop. Haven't done the IR temp verification yet but at about 220 my cap blows and steam comes out
 
At 210 and the fan not kicking in is a clue. Until you can get the spin on water pump and the dmax fan, do the fan clutch mod where you bend the tab different so it kicks in sooner.

I suck at finding posts,Sorry. Can someone help with a link?

I would suggest doing all the above first. If that doesn't get you where you need to be, maybe the Evans waterless coolant?
 
spollock818 said:
Do we think the spin on clutch is better?
Click to expand...

I don't think its the clutch necessarily but the water pump is the key to the spin on clutch. Iirc the later water pumps with spin on fan are appreciable higher gpm flow ( can't remember maybe 30 more gpm) and are suppose the have better flow characteristics in the heads (helps even out the balance between heads). I believe one hot head can raise the gauge temp more than raise the radiator temperature.

Its my understanding the higher flow also normalizes the radiator and helps more uniform temperature of air that washes over the fan clutch thus the system works better.

What ratio of coolant are you using? If too high ratio of coolant the heat exchange is not as good. I am not opposed to the dex cool and have not changed but the green has a higher specific heat index I believe. Evans is suppose to be even better.
 
You must log in or register to reply here.
Back
Top