[landtank]

History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame.

This outlines how I adjusted the timing on my clutch.

warning:none of the parts within the clutch are serviceable by TOYOTA. Be gentle with that O-Ring. If it appears to have stretched and there is a bubble when placed in the groove, simply start from the side opposite the bubble and work it back into place compressing it as you go.

Needed tools:

12mm box wrench to remove the fan/clutch assembly
10mm socket/ratchet for removing fan from clutch
#3 Philips screw driver
#2 Philips screw driver

Supplies:

2 tubes of Toyota 6000 cst oil P# 08816-06001

Attached are pics of the blue hub clutch, the thermometer and oil I used.

[landtank]

Once the clutch has been removed from the truck it needs to be placed hub side down so the oil will drain into the bottom of the clutch. I have always allowed this to happen overnight to be sure all the oil has migrated.

Before disassembly clean the outside of the clutch completely so no debris will enter it upon opening it up.

Start by removing the 8 screws indicated in the pic with a #3 Philips screw driver.

Once the screws have been removed the two half can be separated, there will be some suction while doing this.

Be sure to keep the clutch horizontal, otherwise the oil will run out.

[landtank]

Once the two have been separated the half with the spring on the outside needs to be warmed to 95*.

What I've done is to place about an 1.25 inches of water in a sauce pan and heat it to about 110*. I then placed the control side, spring down into the pan and place the pan on a wooded cutting board. The cutting board helps slow down the cooling process so I have time to make the adjustment.

Since the pan with water in it will cool at the edges faster than the center where the spring is at, it's important to occasionally lift the clutch up and down to help circulate the water and minimize that effect. I did this every few minutes and then more frfequent when I got closer to the target temp.

Attached is a pic of how I had it set up.

[landtank]

Once you've reached 95* it's time to adjust the control plate.

There is 2 #2 Philips screws that once loosened the plate can be rotated.

You'll need to sight threw one of the small round holes and adjust the plates position so that half the hole is open and the other half is blocked by the valve.

If the holes don't align perfectly to each other one should be 50% open and the other should be more than 50% open.

Attached are two pics that show an open hole and one adjusted properly.

The top pic is when the temp of the clutch is greater than 95* yielding an open hole.

The bottom pic is after the control plate has been adjusted by rotating it into position once the temperature has reached 95* You can see that the valve is dissecting the hole leaving half of it open

[landtank]

The last step is to drain and fill the oil in the clutch assembly.

The first pic shows how I positioned the clutch to allow the oil to drain. This will take a few hours minimum, overnight would be best.

The second pic shows where I filled it to. I basically filled it to the underside of the drive plate. Looking threw the holes in the plate you'll see some rectangular reliefs that will help you in determining when you've reached the underside of the drive plate. If you are using the OEM oil empty both tubes completely into the clutch.

You'll want to add oil to all the holes as this stuff is pretty thick and doesn't flow easily.

Now replace the top of the clutch and tighten down the screws. If the O-Ring has come out of it's groove you'll need to work it back into place. The easiest thing I've come up with is to start from the opposite side and work it in by compressing it together. Once it's in place it will stay there during reassembly.

The torque spec that I've come up with for those screws is: Good and tight!


As a last note: Before adjusting the clutch you should scribe the plate where the heads of the screws are so you could put it back to it's original location if need be.

[MTNRAT]

Huh?

[cruiserdan]

Originally Posted by MTNRAT

Huh?

LOL!




Rick has boldly gone where no man has gone before.....

[e9999]

excellent writeup and no doubt good detective and engineer work!

quantitative results?

[landtank]

Originally Posted by e9999

quantitative results?

Not sure what you're looking for, but on Friday I had a 2 hour drive home with a 3500 lb trailer in tow in 90*F weather and I managed to only have slight movement in my RavenTai modded gauge while getting 12.65 MPG.

All in all I'm very satisfied with both the cooling and MPG numbers. Last year I was recording highway MPG numbers in the low 16s. Once I get a few tanks of highway use under my belt, I'll have a better idea how much this adjustment impacted that.

[Beowulf]

Rick,

Step #4 is a little confusing to me. The pics of the 2 holes appear identical and the explanation has me a little confused.

Is the "desired" relationship of the 2 holes at 95* with the 50% overlap? ... or perfectly aligned (no overlap)?

-B-

[landtank]

B, I enlarged the pics and reworded it, let me know if it is still unclear.

[cruiserdan]

To confirm, these guys (in red) are the ones you loosen? Also, how close to center of the slots were they before you started?

[landtank]

Yes Dan, those are the ones you loosen to rotate the plate and the plate was no where near center when I first opened it up. It would be only a guess if I was to make one but I really didn't move it that much as far as distance goes. But the move was in the counterclockwise direction when looking down from the top.

In that other thread Tools posted a pic from when he opened up his and if you compare them they look pretty close visually.

[cruiserdan]

Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

We need to have OZcal call his local Toyota agency and ask them what the part number is for a 1FZ clutch. It would be interesting to see if it's different. Also, what color the hub is.

[Rookie2]

Rick,

Nice write-up. It's hard to tell from your cook picture, but I presume the spring half of the clutch is fully submerged in water? What did you do to insure all the water was out of the unit before reassembling?

Thanks,
Rookie2

[landtank]

Originally Posted by Rookie2

Rick,

Nice write-up. It's hard to tell from your cook picture, but I presume the spring half of the clutch is fully submerged in water? What did you do to insure all the water was out of the unit before reassembling?

Thanks,
Rookie2

The unit is only placed in water, contacting the outside of the clutch, but the spring is submerged. The water isn't high enough to actually enter the area that would be inside the clutch once re-assembled.

[LandCruiserPhil]

Rick Why 3000cst? Seems like the break down of the fluid is one of the main reasons for performance loss of the blue.

[landtank]

Originally Posted by cruiserdan

Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

I'd expect that as well, maybe if a few more go through this we might be able to shortcut the cook all together. But I was thinking that maybe something on mine shifted since the factory and if that were true than the amount might be different for different clutches.

[landtank]

Originally Posted by LandCruiserPhil

Rick Why 3000cst? Seems like the break down of the fluid is one of the main reasons for performance loss of the blue.

That is what looked to be installed in the first place. In my case I don't think it was break down at all, just not coming in soon enough. But I did add some oil to the fill in hopes that by increasing the volume I might provide some additional cycle time to help in cooling it. Also keeping the rad temps down helps in this area as well.

If someone thought it was simply a case of spent oil, they could buy just the oil and drain and refill. It was around $12.00 a tube IIRC. 3 tubes might do it but I can't be sure.

[Tools R Us]

Originally Posted by cruiserdan

Based on the way Toyota does stuff I would hazard a guess that the variances from clutch-to-clutch would be minimal and a guy could just open one up and move it about what you did and have very similar results.

We need to have OZcal call his local Toyota agency and ask them what the part number is for a 1FZ clutch. It would be interesting to see if it's different. Also, what color the hub is.

If the OZ contact could find out what oil is the "A" code, most popular there, I hear it's 10,000 cst?

On the valve, some when opened are even on both holes, others are slightly off, one hole open a little more than the other, this isn't a problem. The idea is to get them about half open between the holes, If one is 40% open and the other is 60% or whatever that's OK, it's not that critical just an indicator to set the opening temp by.

Rick's clutch is relatively new, so his oil is probably good. If your clutch is older and is weak the oil is probably broken down, this is the number one cause of clutch failure. To change it pull the clutch apart invert the half's over a preferably disposable container and allow to drain, wipe clean and refill. The fluid is available from Dan, three tubes are the factory fill.

Rick has shown that the clutch can be slightly overfilled and still operate correctly. If your in a hotter area where the truck operates at 100+ often and your going to add fluid, I would top it off with a tube of 10,000 cst.

[landtank]

Along the lines of draining the clutch, I'd think that placing the parts on rack of some sort with a catch pan and put in an oven at say 150* would go along way in getting that stuff to drain more completely out of the base since that side doesn't come apart.

And I'm not against the thicker oil, but for me it was staying as stock as possible unless there was a need for a change. It's still early with this setup as I've only got one loaded drive during hot weather under the belt. A few more trucks and some more miles might reveal a need for heavier oil.

[Tools R Us]

Originally Posted by landtank

Along the lines of draining the clutch, I'd think that placing the parts on rack of some sort with a catch pan and put in an oven at say 150* would go along way in getting that stuff to drain more completely out of the base since that side doesn't come apart.

Agree, heat helps speed it up, also moving, changing the angle slightly during the process. I have used coffee cans, foam, plastic picnic type plates, piles of rags, etc.

Originally Posted by landtank

And I'm not against the thicker oil, but for me it was staying as stock as possible unless there was a need for a change. It's still early with this setup as I've only got one loaded drive during hot weather under the belt. A few more trucks and some more miles might reveal a need for heavier oil.

That was my thought when I saw the adjustable valve last year, your experiments show it has a positive effect and maybe all that's necessary in cooler environments.

I talked briefly to the engineer about it, then sent him pictures of the clutch and fan with a note listing clutch capacity, our temps, etc. He was very impressed with the clutch and fan design, but said "what were they thinking putting 3000 cst in it? My recommendation would be some where between 15000 - 20000 cst, a good starting point for testing would be 17000 cst!" His thought was that adjusting the valve was like putting a cooler thermostat in an overheating system, masking the real problem, an under performing radiator. It may get a head start on over shearing, but having the proper fluid would make for a more robust system.

He talked like a knowledgeable "car guy" but doesn't own a LC or ever worked on one and works for a company that sells silicone fluids, but he took the time to talk to me about our problem and sounded like he was interested in helping to solve it. I didn't get the impression that he was selling me and I think he realized that the quantities that I would buy wouldn't have an effect on their bottom line. So I classify his advice as honest, good input.

My thoughts on it; I have run thicker fluid in customers and my rigs with good results, all older style fixed valve clutches and 3.0's and 22R types, never a LC. So I don't have as strong of a "non stock" mod aversion and the fluid I have run up to this point has been from Toyota. My fan clutch was weak in my '90, 3.slow, Runner when I got it with ~100K, replaced the fluid with Toyota 10000 cst and never had a cooling, fan or clutch problem, wheeling, towing, etc. sold it with 200K, with the ring fan no less!

The part that I wasn't ready for, at all, was the 17000 cst recommendation! I was thinking in the 6K-10K cst range, so that is well outside of my comfort zone. But his argument for it sounded good and think I will start at 15000 cst and see what happens? Hopefully no exploded fans!

[MTNRAT]

I get it now.
All I saw was 4 separate posts. One was 111 the next was 222 and so on. LOL
Cheers,
Sean

[landtank]

Originally Posted by MTNRAT

I get it now.
All I saw was 4 separate posts. One was 111 the next was 222 and so on. LOL
Cheers,
Sean

That was to keep impatient posters at bay.....worked great

[landtank]

Kevin, I've been first field tech on quite a few new to market machines over the years. And in a situation such as this where you have a high quality part that just doesn't seem to be doing the job quite right, I've come to a basic idea on this.

That is, the easiest least intrusive change that yields the greatest positive improvement is most likely at the heart of the issue.

Maybe that guy is right, but considering the fact that with no fan engagement at all it took 90*+ heat for my truck to approach AC cut off when unloaded says something about how well these systems are designed and how little help they need from the fan to control their temps.

I realise that you've been down this road before with other trucks but for me it would be nice to see you just tweak the timing as I have before upping the viscosity just for some continuity between what I've done and where you're headed.

[flintknapper]

Delete

[Tools R Us]

Originally Posted by landtank

Kevin, I've been first field tech on quite a few new to market machines over the years. And in a situation such as this where you have a high quality part that just doesn't seem to be doing the job quite right, I've come to a basic idea on this.

That is, the easiest least intrusive change that yields the greatest positive improvement is most likely at the heart of the issue.

Maybe that guy is right, but considering the fact that with no fan engagement at all it took 90*+ heat for my truck to approach AC cut off when unloaded says something about how well these systems are designed and how little help they need from the fan to control their temps.

I realise that you've been down this road before with other trucks but for me it would be nice to see you just tweak the timing as I have before upping the viscosity just for some continuity between what I've done and where you're headed.

Rick I agree 100% with your method and like I said it may work in your area, time will tell.

The rest of my rambling was aimed at others who may try this mod, if the clutch is older and weak, changing the fluid while it's apart is probably a good investment. If it's operated in a hotter climate thicker fluid will probably be beneficial, but is totally untested at this point.

[Beowulf]

Originally Posted by landtank

B, I enlarged the pics and reworded it, let me know if it is still unclear.

Pics and wording made it more better. Thanks.

I'm a little behind you guys in understanding exactly what is happening. The 2 changes at once (temp adjust + more fluid) has me questioning if one or both are needed... I need to do some more reading of the prior threads. I get Kevin's idea of a heavier silicone oil and can see that logic.

I think there are a couple of guys with middle-east spec 1FZ-FE's. It would be interesting to see which fan clutch they get? (p/n if possible)

-B-

[landtank]

Originally Posted by Beowulf

The 2 changes at once (temp adjust + more fluid) has me questioning if one or both are needed...

In that other long and winding thread you'll find that I actually did these two things separately. I advanced the timing, then added oil and then advanced the timing again. Adding the oil didn't produce any added benefit as far as lower temps but it didn't add any negatives either such as locking up the clutch when it wasn't needed.

The reason I left it in there is that the oil circulates through the clutch and the larger the oil capacity, the longer it takes to exchange the oil through the clutch and the more time it has to cool the oil. The same idea of having a large sump in the oil pan. The oil will cool better and last longer.

[semlin]

rick great job on this. i am confident this will become as widespread as the temp gauge mod once people figure out the benefits it offers

i have done the mod without adding oil and i think adding the oil is needed. without adding oil the blue clutch offers minimal cooling until it fully locks up. My old original fan clutch noticeably outperforms the new one even with the blue one advanced to 110. my blue one has less than 3000 miles and looks like new.

btw, the screws were exactly centred on my clutch and the clutch fully opened at 116 not 120, which could just be meat thermometer calibration. oil level was very slightly higher than Rick's when I opened it (just spilling over the shelf inside the hole) but it had several days to drain so even that may be a wash.