Fan clutch solves overheating

[bigbrowndog]

Just looked this up to find out what cSt means. It looks the same to me...
search showed...
The standard unit used to measure viscosity is the centistoke (cSt). According to the Automotive and Industrial Lubricants Glossary of Terms:

Viscosity is ordinarily expressed in terms of the time required for a standard quantity of the fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. Since viscosity varies inversely with temperature, its value is meaningless unless accompanied by the temperature at which it is determined. With petroleum oils, viscosity is now commonly reported in centistokes (cSt), measured at either 40°C or 100 °C (ASTM Method D445 - Kinematic Viscosity).

The centistoke rating is converted into the SAE weight designation using a chart like the one shown on the Superior Lubricants Web site.

 

[Tools R Us]

I'm finding plenty of places that sells the oil in 50ml bottles, but it is in weight measurements. Like 3000wt, 10000wt and so on. The prices are likw 8.00 a bottle which would seem to be a single charge for our clutches.

I just can't confirm if the wt class is the same as cSt.

They use it in the diff gearbox of RC cars.

Cool deal, the hobby store bottle I have (100 wt, very thin) is 10ml and was $9.95. We use a trace amount in some of our rocket fuel formulas as a plasticizer. For the fan clutch to work properly we need pure silicone fluid, wonder if the hobby store stuff has additives? It's for "diff lock" on RC cars, so it may work on the same principle? The same fluid is used in the viscous coupler on our trucks.

The tech rep from Clearco is suppose to call in the morning, hope to get some questions answered. But they start talking about stuff like Newtonian fluids, pseudoplastic changes, rhealogical behavior, etc., that stuff starts sailing by me and I am not as fast as Beowulf at goggle so I fall behind!

 

[Rich]

Time to dust off the Brookfield viscometer.

 

[landtank]

I also stumbled on a chemical place that sold gallon jugs of 12500cst for $39.00.

I'm stopping by a few hobby stores tomorrow to see what I can scrounge up.

 

[lowtideride]

So can you mix the thicker new fluid with the older fluid, just to top it off?

 

[cary]

So can you mix the thicker new fluid with the older fluid, just to top it off?

With oils yes, with Silicon, I have no idea. Try searching for silicon weight blending on google.

 

[Tools R Us]

Talked to the rep, have samples on the way 10,000cst and 30,000cst. Pure silicone fluid from them is about $100 a gallon depending on viscosity.

Some notes; The fluid can loose some of it's shearing properties under extreme shearing and/or over 250F this should be reversed when shearing and/or heating stops, returning to it's original properties. Above 300F it can be permanently damaged. Some of the flow and shear characteristics change under shear in the higher viscosities, so using higher viscosities is not intuitive and testing is necessary.

He stressed that for our application we are looking for 100% Polydimethylsiloxane Silicones that do not contain additives or solvents. There are blends of oils some having additives that will reduce the shearing ability and breakdown at temp. Polydimethylsiloxane is blend able, if you mix viscosities the resulting viscosity will be determined by the percentage of the mixed viscosities, 50% 10,000cst and 50% 30,000 will be very close to 20,000cts.

He's sending technical info, will post it when it gets here.

 

[sportbiker929]

In the past while servicing a H-53 drive shaft vibration isolater, we would mix old and new silicone fluid. What ever the MIL spec stuff is.

Mitch

 

[cary]

Polydimethylsiloxane is blend able, if you mix viscosities the resulting viscosity will be determined by the percentage of the mixed viscosities, 50% 10,000cst and 50% 30,000 will be very close to 20,000cts.

He's sending technical info, will post it when it gets here.

If you do a search on bobistheoilguy.com you will find a link for a viscosity blending calculator that will make it easier to see the results of proposed mixes.

 

[locrwln1]

New fan clutch is installed. I did everything I could to get it to overheat. I ran up a pretty steep hill with the air on at 80mph and nothing. I took it into the hills and did several steep, slow hill climbs and a couple of miles of dirt road all with the air on and no problems so far. The only downside to my testing was that its only in the high 80's today and overcast. More difinitive test when the temperature climbs back up.

I'll try and get the pictures uploaded in a few minutes.

 

[locrwln1]

Another shot of the new and two of the old. The new Hayden is smaller in overall diameter that the old one.

 

[landtank]

got myself 1.75oz of 10k at the hobby store. It looks to be the correct consistancy according to the food chart.

When I get home on Friday I'll start the proceedure of swapping it in..

Tools, 30k is going to be some thick stuff.

locrwin1, when you say overheat what are you refering to. No needle movement or not just running in the red?

 

[locrwln1]

locrwin1, when you say overheat what are you refering to. No needle movement or not just running in the red?

Before, the needle would move up to the 3/4 mark and the air conditioning would shut off. There was no needle movement and the air remained cool the whole time. The needle stays in the middle.

Jack

 

[landtank]

Before, the needle would move up to the 3/4 mark and the air conditioning would shut off. There was no needle movement and the air remained cool the whole time. The needle stays in the middle.

Jack

So you have a stock (un-modded) temp gauge then. Modding that gauge would be of some help to us as it would better show temperature variances.

 

[alia176]

Before, the needle would move up to the 3/4 mark and the air conditioning would shut off. There was no needle movement and the air remained cool the whole time. The needle stays in the middle.

Jack

So, the way I understand it, 3/4 mark in the gauge can mean that you're about to overheat. On my gauge (after the temp gauge mod), my A/C would cut off at the highest point of the gauge, which is where I think it should be.

This is a good example of how dumbed down the oem gauges can be!

BTW, I have a hard time believing that you went 80mph UPHILL with the A/C RUNNING at 5,000' elev. Me thinks you're full of poo

Ali

 

[semlin]

3/4 on a stock gauge is 238 which is overheated in my book but not toyota's.

https://forum.ih8mud.com/showpost.php?p=1232378&postcount=15

 

[BROKEROB1]

3/4 on a stock gauge is 238 which is overheated in my book but not toyota's.

https://forum.ih8mud.com/showpost.php...8&postcount=15

Agreed..... after towing 7500 lbs this a couple of weekends ago in 95 degree heat, my AC would cut out in OD on moderate grade hills.... once I kicked OD off, AC would kick back on. When the AC kicked off on the orginal MR T gauge, I was just a shade above the halfway mark... just another data pt

In normal condidtions, no issues with overheating, etc

 

[locrwln1]

So, the way I understand it, 3/4 mark in the gauge can mean that you're about to overheat. On my gauge (after the temp gauge mod), my A/C would cut off at the highest point of the gauge, which is where I think it should be.

This is a good example of how dumbed down the oem gauges can be!

BTW, I have a hard time believing that you went 80mph UPHILL with the A/C RUNNING at 5,000' elev. Me thinks you're full of poo

Ali

It's all about the momentum baby. And miracles of miracles, it was US 395 north out of Reno. You mean the Power button doesn't add power?

My temp guage is unmodded. I haven't had the time or inclination to rip the dash apart to do the mod.

 

[Tools R Us]

One of the emails from Clearco and attached pdf files;

Thank you for your time on the phone, today; it was a pleasure to talk
with you. Attached are specs for the PSF-10,000cSt and PSF-30,000cSt.
These fluids are 100% hi-viscosity polydimethylsiloxane fluids (CAS #
63148-62-9). They will remain stable for long periods at 180C (open
system - presence of air) and the thermal stability is increased in a
closed system.

The behaviour under shear is essentially rhealogical. They can endure
extremely high shear stesses with no loss of properties. When the shear
stress subsides, they return to their original viscosity.

Samples will be sent today. Please contact me after you have some data
from testing.

http://www.copperstatecruisers.org/...ar-RhealogicalBehaviorunderShear(Clearco).pdf
http://www.copperstatecruisers.org/...esforSiliconeFluidsinOpenSystems(Clearco).pdf

 

[Tools R Us]

I also asked what is a good solvent to remove the old fluid with? The units we are removing it from have nooks and crannies (tech term so it will need to evaporate cleanly and not contaminate the new fluid?

I would recomend a strong solvent such as an acetone or
a Xylol to remove the silicone.........silicone is pretty tenacious in
sticking to the surface.

And linked to this;
http://www.clearcoproducts.com/pdf/library/Solubility1.pdf