Renewing viscous coupling clutch fan - DIY

[spectra]

Got 2 18ml tubes of toyota silicone based clutch fan fluid and did this to my Lucida

[spectra]

Getting earlier engagement of fan now. feels safe. Peace of mind.

[VCheng]

Was the old fluid low or just deteriorated?

[spectra]

It was not discolored but looked like battered. Just removed some of it and renewed it. It seems over filled now, will check again if i have left enough room for expansion

[VCheng]

The proper level is just as important as the viscosity.

[spectra]

Any guidelines?

[VCheng]

Getting the fluid level right is important:

The minimum amount fills the outer rim past the depth of the fins.

The maximum amount is when the reservoir in the front is full and overflows through the central hole.

Somewhere between the two should work just fine.

[spectra]

Can u point out what are fins and outer rim?

[VCheng]

The 3 concentric rings are the fins; they should be covered. The reservoir and the central hole are in the middle. To me it looks like you have the level between the two.

[Xulfiqar]

the fan should not run past 2500 engine rpm on a RWD toyota C diesel, it will fracture itself. Make sure its not doing that.

The toyota design is quite good and repairable, where you can see how much fluid is needed, I did this on my Mercedes Benz diesel a year ago, its clutch cannot be taken apart, you can only remove the BMS, its piston and fill it with a needle, it would take you about 4 or 5 tries to get the level correct. First time I overfilled it the fan was coupled right up to 5600 rpm (engine redline).

You can change the temperature in the toyota fan clutch, just rearrange the BMS so its a little tense, but you should not need to do it unless you are going offroading.

[samhassnn]

Hi Spectra, could you please tell me where you got the silicon tubes? I would greatly appreciate your most helpful reply.

[Xulfiqar]

If you are in the US (according to your location), go to a hobby store that sells RC stuff, and buy 3000 cst diff oil, it will cost you a grand total of 5 to 8 dollars for 2 Oz of it. If in Pakistan note this part no, and get it from a dealership, the cost should not be more than 12 dollars (convert to rupees).

[spectra]

Hi Spectra, could you please tell me where you got the silicon tubes? I would greatly appreciate your most helpful reply.

@ Sameed bhai

I got it from Hamza younas autos Saddar Rawalpindi, they are stockists for genuine toyota parts and many delaerships but stuff from them. It costs 750 per tube, for a complete fill i think you will require 2 of them. numbers are 0515519107, 0515565178

it must be available in lahore as well, but i am not familiar with lahore market at all.

[spectra]

And the one available is 3000cst as most toyota fans use this fluid. few use 6000cst

[Xulfiqar]

And the one available is 3000cst as most toyota fans use this fluid. few use 6000cst

The HD - desert duty land cruiser and van clutches use 10,000 cst.

[Xulfiqar]

It is best practice to let the clutch drain for about 2 days to ensure all old fluid gets out, the old fluid gels and grabs too hard. a fan working overtime will cause air to stall at the fan and eventually heat up.I learnt this from refilling BMW and MB clutches - I dill a small hole in their hold chamber and suck out old fluid, then fill with 200 cst fluid and put the clutch on a drill to spin it and remove the freshly added fluid, it cleans it out too, then add 3000 cst fluid, that way the clutch very softly couples and releases at speed - its the best in cooling, using too thick fluid causes great volume of air to be pulled but a BMW or MB engine bay is very cramped and the clutch action is very thought out by the manufacturer.

[spectra]

Air stalling is not an issue i my estima because engine is way back in the chassis. but still over connect of a fan can be fatal at a critical time. Tuning a clutch fan is more of an art then a science in my opinion. This is based on my own experience so far

[Xulfiqar]

your fan should have 1 disengaged position and 2 engaged positions, the 1 disengaged is the fan completely freewheels regardless of pulley rpm on a cold engine (it should be engaged when first spun up)the mid position is soft couple - you cannot hear any roar but the fan would be sucking quite a bit of air, this is normal operating temperature, the final is full tilt - it will sound like a passenger jet applying air brakes on landing. This is engine hot position.The clutch should disengage above 2500 or 3000 engine rpm regardless of outside temperature, this is done to keep the fan from fracturing and also reduce HP losses by the fan.

[Moderator]

[Moderator]