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

[landtank]

Where did you find cold weather? That's with 5K oil, right?

Utica NY, only for a brief time. Yes I'm still running the 5K OFNA oil. I'll split the clutch apart in the spring and see how the oil looks. The OEM would be an amber color by then and I'm interested in how this stuff looks.

The needle fluctuates about a width and a half or so when driving in cooler weather. It's nothing that I'm concerned about at all, just giving some follow up info.

 

[semlin]

the mileage hit right now in the cold weather is getting very significant and the cold fan roar is more noticeable. I'm losing at least 2 mpg in town and 1 mpg on the highway.

 

[landtank]

the mileage hit right now in the cold weather is getting very significant and the cold fan roar is more noticeable. I'm losing at least 2 mpg in town and 1 mpg on the highway.

Once I get into winter temps maybe I should swap out the oil and see what happens. Since I drive basically the same route and at a 700+ miles per week I could get some great info fast.

 

[NaterGator]

Er.... haha... a stupid question perhaps, but how does one keep the water pump pulley from spinning while trying to loosen the nuts to get the old clutch off?

Feeling rather dumb right now...

edit: nvmd, looks like I need to go buy a 12mm 6pt wrench, 12pt it just asking to round these nuts.

 

[semlin]

break'em loose with the open end of the wrench. you should be able to get enough friction by leaning on the belts, or, failing that, by jamming a large screwdriver in there.

 

[RavenTai]

edit: nvmd, looks like I need to go buy a 12mm 6pt wrench, 12pt it just asking to round these nuts.

I ran into the same thing changing my clutch, bought a set of 6pt metric wrenches shortly after.

 

[NaterGator]

No dice, no how. These fxxxers are seized well. This looks like the original fan clutch, and the nuts feel like it too.

Tried breaking them with the open end and a bit of hammer, one nut started to round. Used the gear end of the wrench and a bit of hammer, another nut began to round. Before I do any more damage I'm going to give them a week or two of treatment with PB blaster. Barring that I am out of ideas to get them off. Should they round any more I may be in quite a damn pickle.

Oh the problems I've been having with my nuts lately I've got my modded fan clutch all ready to go in (feels better with the 6k fluid in it!) but I must wait for cooperation from the cruiser. Grr.

 

[RavenTai]

worst case you can try a nut splitter then get new nuts, hopefully your other problems will not go that far.

 

[semlin]

try soaking in pb blaster for a few days then try again.

 

[NaterGator]

worst case you can try a nut splitter then get new nuts

True, they do seem quite soft and I bet they would be easy to split off.

*sigh* Cdan? Should I order these nuts from you or get them at my local ace hardware?

 

[NaterGator]

Just got back from sears with a new good 6 point and the typical craftsman nut splitter just in case. Doused them with a bit of PB and I'll let it sit for a while before I hack them up again.


A tip to those of you doing this: it helps immensely to use a glass bowl as a catcher and to stick both halfs of the clutch in the oven while they drain. My oven can hover at 150°F but I chose to cycle it on and keep the temp around 130. Either way my clutch drained alot faster and it took maybe 3 hours to get 98% of the old oil out. Also, if you stick your new tubes of oil in hot water for a few minutes before you fill your warm clutch they will flow easier and fill the clutch faster.

 

[NaterGator]

PB and the better wrench did the trick. Just got the assy off the truck and am swapping the fan now. Thanks guys!

edit: Just finished up and heard something I've never heard before... fan roar! Underhood airflow is noticeable and I think this is going to cool much more effectively. I'll post back results as summer kicks it up a notch, but for now everything looks favorable! Kudos to all who pioneered this mod.

 

[Tools R Us]

PB and the better wrench did the trick. Just got the assy off the truck and am swapping the fan now. Thanks guys!

edit: Just finished up and heard something I've never heard before... fan roar! Underhood airflow is noticeable and I think this is going to cool much more effectively. I'll post back results as summer kicks it up a notch, but for now everything looks favorable! Kudos to all who pioneered this mod.

Six point wrenches are recommended, there isn't much room to use a nut splitter and probably don't want to use a lot of force, like hammer and chisel on them, that shaft is supported by the water pump bearings. For replacement nuts, I would order from Dan.

The thicker fluid makes the clutch work like it should have from the factory, much more airflow!

 

[NaterGator]

Here's the old one that came out....

 

[Tools R Us]

It looks like the shaft seal was leaking?

 

[NaterGator]

No I have leaky oil pump gasket and I think a leaky distributor so I get a light misting of oil combined with dirt all over the front of my engine. I've been meaning to fix the oil pump cover but I don't have the tools at my apt at college. I tried cleaning the engine off but there are simply some areas on the front of the engine that I cannot reach to degrease. Oh well.

 

[EricE]

Theory of Fan Clutch operation
How does the fan clutch work? It seems to me that if oil is to cause the lockup and slippage then it would work in reverse of how it needs to. It would slip when hot and lockup when cold. What am I missing?


I think I read most of this thread but I don't get it.

 

[landtank]

The temperature valve on the front allows or restricts the flow of oil into the shearing area. No oil to shear no drive, lots of oil to shear lots of drive.

When the truck is first started some of the oil has settled into this shearing area and the initial roar is it pumping it out. This initial roar soon subsides because the engine is cold and the valve is restricting the oil from flowing back into the shearing area.

 

[EricE]

The temperature valve on the front allows or restricts the flow of oil into the shearing area. No oil to shear no drive, lots of oil to shear lots of drive.

When the truck is first started some of the oil has settled into this shearing area and the initial roar is it pumping it out. This initial roar soon subsides because the engine is cold and the valve is restricting the oil from flowing back into the shearing area.

So the spring heats up from...where? Does it heat up from ambient air temp or is the heat conducted from the engine through to the spring?
So the spring causes an opening of these holes (when it gets hot) which allow oil to flow into the shearing area. Good so far?
Is this spring also the force which pushes the oil back out of the shearing area or is that some other force?

 

[landtank]

So the spring heats up from...where? Does it heat up from ambient air temp or is the heat conducted from the engine through to the spring?
So the spring causes an opening of these holes (when it gets hot) which allow oil to flow into the shearing area. Good so far?
Is this spring also the force which pushes the oil back out of the shearing area or is that some other force?

The spring is on the front of the housing facing the radiator. It is influenced by the air that has passed through the radiator.

The shearing action also acts like a pump to more the fluid back into the reservoir. So when it's engaged it's constantly cycling the fluid through the clutch.