Fan clutch solves overheating

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landtank said:
So how big are these samples?

I ordered 4 oz. of each, 10,000 cst and 30,000 cst. It's much more expensive in "sample quantities", if testing shows that say, 17,000 cst works best they can blend it for us in the gallon size.
 
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landtank said:
enough for 2 clutches then.

1.7 oz for a fill, so 4 fills? Plus I have some Toyota stuff from Dan, so the playing will commence when the samples arrive.:hillbilly:
 
Tools R Us said:
1.7 oz for a fill, so 4 fills?

I was thinking 2 fills per type.


Just took the clutch apart. Looks like there was plenty of oil in it. Oil was golden in color and seemed in good shape. No where near as thick as the 10k stuff I got.

Tools, any way to remove that ringed disk from the drive side of the clutch? Or do you figure on letting it drain over night and flushing with acetone in the morning.
 
After looking more closely at the innards I'm thinking the first step I'm going to do is to try and come up with a calibration method for setting that control ring.

Any thoughts on what air temp that spring should see when STARTING to allow fluid to flow. This would be when the clutch just begins to provide some drive to the fan.

I'll do a test tomorrow and report back where my clutch was set at.
 
landtank said:
...

Just took the clutch apart. Looks like there was plenty of oil in it. Oil was golden in color and seemed in good shape. No where near as thick as the 10k stuff I got.

That's been my observation on the majority of them that I have had apart.

landtank said:
Tools, any way to remove that ringed disk from the drive side of the clutch? Or do you figure on letting it drain over night and flushing with acetone in the morning.

I have never successfully removed that plate. Your plan sounds good, I would remove the valve plate, mark it first so you know how it was adjusted. If you use solvent make sure it's all evaporated before assembly so it doesn't contaminate the new fluid.
 
I couldn't wait until morning so I did a temp test on the clutch.

It looks to me that there are actually 2 passages for the oil to pass out of the reservoir. The first one to open is the small round one hole that lets oil into the ringed area of the fan. As the temp spring opens further the irregular shaped opening begins to become uncovered and the oil is allowed into the pump area where the real drive is transferred.

That first hole becomes unblocked at 120*. I think this basically provides a small amount of drive to be sure some air is flowing across the clutch.

The second irregular hole doesn't start to open until 135*. Now this would be just the beginning of the oil weeping through to the pump. Drive seems to be controlled by how much surface area around the outer edge is covered with oil. Since it is continuously being pumped away a small trickle wouldn't really do much.

My gut is telling me that this is where my problem is. With the weight of this oil the temp on that spring would have to be over 140* to get any beginning of drive to the fan.

I'm thinking that if that spring is at 140* the water in the radiator has to be even hotter. Anyone have an idea how much hotter?

I'm going to set the plate for an earlier engagement and see what happens.
 
Just my thought, but a plugged radiator could interfear with the operation of the fan clutch. If the clutch depends on heat from the radiator to activate the clutch a plugged radiator will not allow proper activiation. This would occur because the plugged radiator would not allow hot coolant through, causing less heat to be transfered from the radiator into the airstream reaching the clutch and thereby causing the clutch not to activate when it should. It seems this could create a vicious cycle, as then the clutch will not cause air to be pushed through the radiator leading to the engine running even hotter.
 
cary said:
Just my thought, but a plugged radiator could interfear with the operation of the fan clutch. If the clutch depends on heat from the radiator to activate the clutch a plugged radiator will not allow proper activiation. This would occur because the plugged radiator would not allow hot coolant through, causing less heat to be transfered from the radiator into the airstream reaching the clutch and thereby causing the clutch not to activate when it should. It seems this could create a vicious cycle, as then the clutch will not cause air to be pushed through the radiator leading to the engine running even hotter.


Radiator is less than a year old and an aftermarket clutch solved the over heating issues.

For better or for worse I'm completely convinced this clutch has an inherent problem.
 
I just got back from my usual test drive and the truck ran fine. It's 80* out and that first time it ran near the red it was 82* so I think there has been an improvement.

I basically advanced the clutch timing by 15-20* (temp). We'll see tomorrow but the weather here has been rain with more rain to come so no real hot weather testing anytime soon I'm afraid.
 
landtank said:
...
I'm thinking that if that spring is at 140* the water in the radiator has to be even hotter. Anyone have an idea how much hotter?

I'm going to set the plate for an earlier engagement and see what happens.

Agreed, but you probably don't want or need the fan on full speed until the radiator is ~200F?

The air coming through the radiator isn't at radiator temp, then add in air leaks around the fan and shroud edges, etc. mixing in cooler air. The fan pulling air makes a slightly negative pressure in the shroud and positive pressure under the hood. The clutch fins aren't angled, so I bet the airflow around the clutch is forward, into the shroud. If this is the case the clutch thermostat is set for fan output, underhood temp?

So who's going to mount a thermocouple in there and get data?:D
 
landtank said:
Radiator is less than a year old and an aftermarket clutch solved the over heating issues.

For better or for worse I'm completely convinced this clutch has an inherent problem.


I second that. Pulled the OEM clutch fan off tonight and guess what - not working. I opened it up and it had VERY little oil inside.

I installed the Hayden I picked up from Pep Boys and it seems to be working - it makes the loud roar at startup - which I didn't have before.

I drove it around with the AC on trying to make the engine hot, but the temp gauge stayed low.

Seems like the Hayden clutch fan cycles on and off - pulling a lot of air and then after awhile winding down - only to turn back on again. Is that normal?
 
Gauge said:
I second that. Pulled the OEM clutch fan off tonight and guess what - not working. I opened it up and it had VERY little oil inside.

I installed the Hayden I picked up from Pep Boys and it seems to be working - it makes the loud roar at startup - which I didn't have before.

I drove it around with the AC on trying to make the engine hot, but the temp gauge stayed low.

Seems like the Hayden clutch fan cycles on and off - pulling a lot of air and then after awhile winding down - only to turn back on again. Is that normal?
Yes, that sounds good. It should cycle like that so it can hardly engage at fast highway speed yet engage fully when the motor is at high revs travelling slow in the indirect gears or low range.
I should have added that from the start up while stationary the fan should increase speed when the engine gets pretty warm. Also as some of you guys start to pull down the fans could you count the number of times it will spin with a flick cold and perhaps warm. Might be worth a comparison especially if you go to heavier oil or have to add more oil cheers
 
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Update/summary

Today I swapped out the Stant T-Stat for an OEM unit.

Way big improvement on temp stability. The needle now has returned to the middle position as before and on my usual test run with outside temps at 84* there was no movement that I could detect in the neddle's position on the gauge.

Another note: Upon turning off the engine I checked the fan's resistance and some resistance could be felt, more than what was felt before the timing adjustment with the engine temps around 230*.

I'm convinced that my clutch was engaging late and allowing my engine to run hot.

Sunday the temps are to be in the 90s so I'll hook up the trailer and do some further testing then.
 
Rick

Assuming that late fan clutch engagement was the problem, why didn't your temp get hot then cool down once the fan eventually engaged? shouldn't you be seeing a wildly fluctuating temp with it dropping down to disengagment temp then building back up?

My suspicion is the stock blue flange fan clutch engagement threshold is so high a temp there is no engagement or perhaps only partial "graduated" engagement so all you ever get is the limited cooling effect from the lightly freewheeling fan. that is enough to keep it from overheating at idle and in cold weather but it can't cope with the heat when there is any load on the motor.

I was driving an old honda civic beater with an electric fan earlier this year and the thermo-switch for the fan was broken. The heating temp behaviour with no fan at all was only a bit more extreme than my cruiser when driving. It would overheat at idle but remember that with an electric set up there is no fan blowing at all when off. I "fixed" it by rigging a manual dash switch for the fan. I could see the engine temp drop when i turned that fan on.
 
I believe that the reason why I don't see the fluctuations is that I'm now cooling the antifreeze to a point where the THERMISTAT controls the temperature.

Before the T-Stat would be wide open and the temperature of the engine was being controlled by the fan clutch.

As of right now I don't think the thicker oil is warranted or even a good idea. I did loose some oil when I had it apart and tried to contact CDan for a tube to work on how to gauge when these things are at the proper level. I have an idea for that as well.

FYI: I just didn't wildly adjust that control disk, I can repeat this over again.
 

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