Fan Clutch Oil Change (1 Viewer)

[1JZGTE]

Hi guys, I been doing some baking in the oven today

So I split the clutch, drained all the oil, put the half that opens up in the oven, propping the clutch up by screwing it into a piece of timber.
My theory is that this setup would sort of replicate what the coil spring sees inside the engine bay in terms of heat (I read here that the water and pan method is not ideal?)

I'm using a meat probe thermometer, not great as it needs to be stuck into something to work, so I don't know how accurate the readings are, but I don't have anything else to hand for the job.

Things I noticed and would like to report back:

1. Only the small 0 shaped windows opened up once the temperature on the thermometer got to 65C / 149F. At 50C / 122F, it was still fully closed. Is that OK on the basis that my thermostat is rated at 82C / 180F? Or should I try to make some adjustments so it opens up full at 80C and over?

2. The boot shaped holes (highlighted red), didn't open up at all (just the 0 shaped holes open), not even when I heated the oven up to around 120C / 248F! I note in previous posts that the boot shape opens up, well mine doesn't . Do I have a faulty clutch or it was supposed to be like this?

3. Midman asked - my clutch is grey, not sure if it is a good or a bad clutch, I assume it is ok as the car comes from the early 1990s, an era when things were overbuilt and not a massive budget like these days

 

[richardlillard1]

Hi guys, I been doing some baking in the oven today

View attachment 2407503

So I split the clutch, drained all the oil, put the half that opens up in the oven, propping the clutch up by screwing it into a piece of timber.
My theory is that this setup would sort of replicate what the coil spring sees inside the engine bay in terms of heat (I read here that the water and pan method is not ideal?)

I'm using a meat probe thermometer, not great as it needs to be stuck into something to work, so I don't know how accurate the readings are, but I don't have anything else to hand for the job.

View attachment 2407504

View attachment 2407505

Things I noticed and would like to report back:

1. Only the small 0 shaped windows opened up once the temperature on the thermometer got to 65C / 149F. At 50C / 122F, it was still fully closed. Is that OK on the basis that my thermostat is rated at 82C / 180F? Or should I try to make some adjustments so it opens up full at 80C and over?

2. The boot shaped holes (highlighted red), didn't open up at all (just the 0 shaped holes open), not even when I heated the oven up to around 120C / 248F! I note in previous posts that the boot shape opens up, well mine doesn't . Do I have a faulty clutch or it was supposed to be like this?

3. Midman asked - my clutch is grey, not sure if it is a good or a bad clutch, I assume it is ok as the car comes from the early 1990s, an era when things were overbuilt and not a massive budget like these days

I don’t like using the water method because it isn’t realistic to what the clutch sees in everyday use. The method you’re using is decent, but the best way would be to stick the end of a thermocouple in the spring and heat it with a heat gun. It’s the only way to be sure the spring is getting up to the temperatures you want to see. When testing, you’re not looking for the temperature as it opens, you should heat the spring enough to open, then watch it close and record the temperature that way; this is one of the reasons it takes me upwards of 20-30min to tune a clutch (even more if it needs adjustment, but I see that less on Eaton clutches and older black hubs for the 80). If you’re heating metal, it won’t heat up uniformly and it will continue to get warmer as heat is being introduced to it, so knowing the temp of the spring itself is critical. An oven can be set to a specific temperature but there‘s usually a massive heating element nearby (bottom or top if using the broiler setting) getting considerably hotter than the temp you’ve set it to and screwing with your results.

Hopefully that makes sense.

That said, if you’re seeing an initial opening at 122°f, that is just about on the money. When I’m tuning a fan clutch I shoot for around 115-120°f for the first opening. Two degrees puts yours right into that acceptable range, assuming your test was accurate enough to be considered correct.

As for the boot shaped opening, to test that positively, hold a lighter to the spring and see if that makes it open up. I don’t think I’ve ever seen a spring totally fail on a clutch unless the inside is filthy. The inside of yours is nice and clean and your testing method leaves some room for error, so I would be inclined to say either more testing is needed or just fill it with some thicker silicone and see what happens.

As for the question @MidMan asked, Aisin paints the hubs of their clutches. For the 80, it makes reference somewhat easier, but there are still issues. The two Aisin colors for the FZJ80 are black hub and blue hub; their designs are slightly different and the cst used must be adjusted accordingly for this design change. This should make it pretty easy. Except that the early replacement Aisin clutches were a black hub design with a blue painted hub. The increased confusion is why I prefer to just open the clutch up and see what it looks like inside.

The increased shearing area (ribs) is more akin to a black hub In design. More shearing area means a lower cst will net the same results as other clutches.

And the coolant temp has less to do with the fan clutch temp. You’re looking for the temp the air in front of the clutch gets hot enough to open the valve and make the clutch turn on. 180°+ will not translate to the 120° The clutch needs to operate.

 

[Michael Hanson]

Hi, Personaally I would use at least 10,000 oil. I saw very little improvement with lesser weight oil. Mike

 

[MidMan]

Hi, Personaally I would use at least 10,000 oil. I saw very little improvement with lesser weight oil. Mike

Yes, 10,000cst viscosity is the what Toyota generally recommends in most of their vehicles worldwide.

 

[MarcusAurelius]

New blue hub just got in, 15k cst overkill for Montana? I have some 15 k on me other wise it is just what ever amount/weight came with the clutch. Or I could mix it with the stock oil. Also do I need to do this spring test and potentially modify?

 

[richardlillard1]

New blue hub just got in, 15k cst overkill for Montana? I have some 15 k on me other wise it is just what ever amount/weight came with the clutch. Or I could mix it with the stock oil. Also do I need to do this spring test and potentially modify?

The blue hub seems to come out of the box with the valve set all over the place, but usually within some sort of acceptable range. Given your local climate I would guess a drain and refill would be fine. Luckily it’s one of those mods where if you don’t like the results you can play around with it until you do.

 

[MidMan]

New blue hub just got in, 15k cst overkill for Montana? I have some 15 k on me other wise it is just what ever amount/weight came with the clutch. Or I could mix it with the stock oil. Also do I need to do this spring test and potentially modify?

There are three kinds of Fan Clutches categories by the colors.

Red Fan Clutch
Its good for slow moving vehicles like Garbage Trucks, Plant Watering Trucks, Road Cleaning Vehicles, Towing, etc.
It keeps the fan engage for the longer time and hence sucks more air through radiator fins.

Blue Fan Clutch
Its universal clutch for all types of passenger cars suitable for all seasons.

Black Fan Clutch
Good for Cold areas mostly.

Please keep using the Blue Clutch as you receive. There is absolutely no need to change/replace the silicon oil inside.

Ideally, I guess you should have Black Fan Clutch. But its OK. you can use the Bluc Clutch as well, but without replacing the oil in it.

 

[MidMan]

There are three kinds of Fan Clutches categories by the colors.

Red Fan Clutch
Its good for slow moving vehicles like Garbage Trucks, Plant Watering Trucks, Road Cleaning Vehicles, Towing, etc.
It keeps the fan engage for the longer time and hence sucks more air through radiator fins.

Blue Fan Clutch
Its universal clutch for all types of passenger cars suitable for all seasons.

Black Fan Clutch
Good for Cold areas mostly.

Please keep using the Blue Clutch as you receive. There is absolutely no need to change/replace the silicon oil inside.

Ideally, I guess you should have Black Fan Clutch. But its OK. you can use the Bluc Clutch as well, but without replacing the oil in it.

My 80s came with black fan clutch. Previous owner never noticed this.

I changed it to RED after filling 12,500cst oil and its working perfect. Here we have 10 months long summer. And temperatures from End March to End September are like 35~45 degree C
And my truck is running just fine since last 2 years and no over-heat issues at all.

 

[richardlillard1]

There are three kinds of Fan Clutches categories by the colors.

Red Fan Clutch
Its good for slow moving vehicles like Garbage Trucks, Plant Watering Trucks, Road Cleaning Vehicles, Towing, etc.
It keeps the fan engage for the longer time and hence sucks more air through radiator fins.

Blue Fan Clutch
Its universal clutch for all types of passenger cars suitable for all seasons.

Black Fan Clutch
Good for Cold areas mostly.

Please keep using the Blue Clutch as you receive. There is absolutely no need to change/replace the silicon oil inside.

Ideally, I guess you should have Black Fan Clutch. But its OK. you can use the Bluc Clutch as well, but without replacing the oil in it.

My 80s came with black fan clutch. Previous owner never noticed this.

I changed it to RED after filling 12,500cst oil and its working perfect. Here we have 10 months long summer. And temperatures from End March to End September are like 35~45 degree C
And my truck is running just fine since last 2 years and no over-heat issues at all.

I don’t know how you’ve come to that conclusion, but there are several 80s out here running black hubs in the desert with no complaints.

No idea what you mean by red clutch, there is a red hub Aisin, but it isn’t for the 1FZ.

The 15k is rather anemic for a blue hub in a lot of warmer climates. We tend to run them at 30k here in the AZ desert, so 15k is not something I would have an issue with running in Montana.

EDIT: I see you’re not in the US and running a 4.2. Totally different ball game than our US spec trucks.

 

[1JZGTE]

Hey folks, just a quick update - I decided not to mess about with the screws that adjust the temperature the clutch engages at after all, as I wasn't 100% sure what the heck I was doing. In the end, I simply heated the fan clutch it up in the oven and emptied whatever was left of the oil (not much) and then I filled one half with a bottle of Team Associated 7,000cst silicone fluid (59ml). I did think that I could probably get more than a bottle in there, but don't know if that would have been a good idea, so left it at that and sealed the whole thing back up again.

Following assembly and reinstall, I had the car idle on the street for a good 25 minutes. Now the downside is that it was only about 70F outside, so a very mild temperature but nevertheless after 25 minutes, the temperature was bang on in the middle, so I think I may have fixed things for now. I hope to test it in warmer temperatures soon!

***Big thanks to all those who contributed - there is certainly a wealth of knowledge on this forum! ***

 

[MidMan]

and then I filled one half with a bottle of Team Associated 7,000cst silicone fluid (59ml). I did think that I could probably get more than a bottle in there, but don't know if that would have been a good idea, so left it at that and sealed the whole thing back up again.

normally fan clutch of 80s takes 50-70ml oil depending on various clutch models.