Blue fan clutch mod...Thread has gone to hell, read at your own risk (1 Viewer)

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Rick are you still offering the rebuild of the New blue clutches?
 
You were at $60 I think? Not sure, if inflation is in order that's fine..

Kirk
 
Sounds good. I'm placing my order with CDan in the next few days. Once the clutch comes in I'll PM you for your address to send it to.

Thanks Again,
Kirk
 
Dan will ship it directly to me and save time and some money.

OK cool I'll make sure to tell him that. I sent him my wish list earlier today.

Thanks,
Kirk
 
As an update as promised.

In cold weather the truck's temperatures now seem to fluctuate more. The truck does get into a cyclic mode where it runs hotter than usual. I think this is do to the thicker oil, it just doesn't flow as fast in the clutch in this weather and there is a delay which allows the engine to run warmer. But once the oil warms as starts to flow the temps come down.

At operating temperature there is very little resistance to movement so it's definitely not engaged.

I have seen a drop in MPG but I don't think it's from the clutch. I've always had high MPG numbers, unusually high, and now they are more in line with everyone else. What changed? I had a front O2 sensor failure and with that new sensor came an improved running engine and a drop in MPG. So right now I'm getting around 14 mpg on the highway which is where a fully loaded 80 usually runs.

Rick, I honestly don't know why now that it is hot here, I'm thinking about this winter post ... but, can you clarify what was happening when the rig was running hotter than usual and with those fluctuations then? IOW, what was the warmer temp reached at warmup before the fan did engage (how much more than regular), and then, am I reading right that after the warmup the rig would still cycle between cool and warm? Have you come to the conclusion that 6000 is too thick for those of us who have winter temps sub-zero? Thanks. :cheers:
 
From what I remember in the summer the truck would run at a constant 185* all the time, no needle movement. But in the winter it seemed to cycle as it couldn't find a nice spot where just enough air would keep it constant.

I never got an actual reading on it but would see the needle on my modded gauge move around.
 
Just an update to this thread:

I'm running the blue clutch with pure 6k fluid. At stoplights my temps will creep up as high as 199°F, at medium speeds it is usually at 191°F, and at highway speeds it is 193-195°F.

All of these temps are hot Florida summer ambient temps running the A/C. My cooling system needs to be flushed, etc, however I'm fairly happy with the change. Before I'm sure they were quite a bit dangerously higher.
 
Just an update to this thread:

I'm running the blue clutch with pure 6k fluid. At stoplights my temps will creep up as high as 199°F, at medium speeds it is usually at 191°F, and at highway speeds it is 193-195°F.

All of these temps are hot Florida summer ambient temps running the A/C. My cooling system needs to be flushed, etc, however I'm fairly happy with the change. Before I'm sure they were quite a bit dangerously higher.

Glad to hear it. This is my plan as well. I have a new blue, and 3 tubes of 6k silicone oil. My climate is hot as well.
 
This is a little too high for my liking. When I had these idling temps I would grossly overheat when towing 3500 lbs in 100* weather. But tyhat was before the oil upgrade and timing adjustment.
There is no doubt in my mind I need to baseline my cooling system better and flush the radiator and have it flow tested, PHH, etc.

I'm just pretty confident I can get away with it for 2 months in NC and then get home and deal with it. Certainly alot better than I could have with that terrible old fan clutch that was in there!
 
I know it's sacrilige to say this but what about using an electric fan with a thermostatic control set around 197 or so and hooked via relay to the AC so that whenever the AC is on you have some additional airflow. You know a front mounted pusher fan. With a cab mounted switch to over-ride fan operation for water crossings.

Now I'm not talking about ignoring the fan clutch issues, just using an electric fan as extra insurance. If the Blue hub clutch with 6000 fluid does it's job then great, otherwise the electric one keeps things cool. If you find that the electric fan cools too much under normal driving with the A/C on but not towing then you can just shut it off with the dash switch.

I'm planning to go this route. I'm going to have LandTank dial in a new blue hub from CDan and install it along with a small electric pusher fan to assist cooling..
 
i'd say a t-stat controlled electric fan on top of a 6000 pst fan clutch is a bad idea. It will interfere with the fan clutch t-stat and you will see big temp fluctuations. The fan clutch will be much cooler than it should be for the engine temp when the electric fan cycles off at 197 so it will not be pushign enough air to prevent a sudden heat increase.

It will also suck even more power from your truck than the amped up fan clutch and I doubt it will increase the cooling efficiency proportionately. you will see gas mileage plummet and with the power loss you will be lugging the engine in the gears the ECU selects so you will heat up.

My experience is that if all you do is overadjust the fan clutch you suck so much power out of the system you can create negative feedback loops where the engine is making more heat trying to move the truck up hills with less power than the fan clutch removes.

That goes double with a truck with inadequate gearing for tire size. With my fan clutch adjusted to open at 100 degrees t-stat for a long tow on stock gears and 33s I found that even when the truck was empty and towing nothing I had to switch o/d off when driving on a small uphill grade or the truck would gradually heat up. Basically, I was sucking so much power with the fan I was lugging the engine. As soon as I turned the o/d off the temp would drop.
 
From what I remember in the summer the truck would run at a constant 185* all the time, no needle movement. But in the winter it seemed to cycle as it couldn't find a nice spot where just enough air would keep it constant.

I never got an actual reading on it but would see the needle on my modded gauge move around.


Rick this is sorta strange to hear; my rig tends the opposite - in winter time I'm almost always right at 80 to 82 Celsius (very limited variability) whereas in summer time I'm basically between as much as 80 to 98 Celsius. IOW, much more variability in the Summer and never really any overheat anytime. I'm wondering if you can take the Auto Enginuity software stuff and really read your Summer temps - I think that you will find much more variability. IF not, well, something has switched with the fan clutch operation either due to the timing or due to the thicker fluid or both. This might warrant more testing on timing or viscosity. :cheers:
 
i'd say a t-stat controlled electric fan on top of a 6000 pst fan clutch is a bad idea. It will interfere with the fan clutch t-stat and you will see big temp fluctuations. The fan clutch will be much cooler than it should be for the engine temp when the electric fan cycles off at 197 so it will not be pushign enough air to prevent a sudden heat increase.

It will also suck even more power from your truck than the amped up fan clutch and I doubt it will increase the cooling efficiency proportionately. you will see gas mileage plummet and with the power loss you will be lugging the engine in the gears the ECU selects so you will heat up.

My experience is that if all you do is overadjust the fan clutch you suck so much power out of the system you can create negative feedback loops where the engine is making more heat trying to move the truck up hills with less power than the fan clutch removes.

That goes double with a truck with inadequate gearing for tire size. With my fan clutch adjusted to open at 100 degrees t-stat for a long tow on stock gears and 33s I found that even when the truck was empty and towing nothing I had to switch o/d off when driving on a small uphill grade or the truck would gradually heat up. Basically, I was sucking so much power with the fan I was lugging the engine. As soon as I turned the o/d off the temp would drop.

In my 4runner I put in the Flex-a-lite dual electric fan designed for the 4runner and removed the factory fan and clutch. I ran it for over a year with no issues, one electric fan was set for cooling and one for a/c.. That's why I started thinking electric fans in the first place. I got a nice little bump in gas mileage outta the deal too. BUT clutch fans are known as much more reliable. However this thread has me wondering about combining the 2. What are your thoughts on a stock blue hub with electric fan set around 200 with no automatic A/C activation?
 
Rick this is sorta strange to hear; my rig tends the opposite - in winter time I'm almost always right at 80 to 82 Celsius (very limited variability) whereas in summer time I'm basically between as much as 80 to 98 Celsius. IOW, much more variability in the Summer and never really any overheat anytime. I'm wondering if you can take the Auto Enginuity software stuff and really read your Summer temps - I think that you will find much more variability. IF not, well, something has switched with the fan clutch operation either due to the timing or due to the thicker fluid or both. This might warrant more testing on timing or viscosity. :cheers:

You're also boosted which might play a role in how much heat the cooling system needs to deal with.
 
You're also boosted which might play a role in how much heat the cooling system needs to deal with.
I am not boosted and my experience is the same as turbocruiser.

You also opened your clutch and changed when the valves fully open, right? I think what is going is that we left stock valving, so we don't go into a cyclical self-defeating loop in cold weather where the clutch engages fully too soon and the truck fights it... however in the summer the clutch may engage fully a little to late so we get higher temps and start to heatsoak before the clutch gets fully open.

Just conjecture though.
 

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