Installing Thermostat

[69hurstolds]

the fan runs all the time, is that normal if it’s a thermal clutch ?

The fan is attached to the water pump hub, so I would totally expect it to run when the engine does. It just doesn't run as fast when it's "cold" as it slips. When it hits the temperature point the clutch locks up and pretty much is 1:1.

If it never locks up, it will slip and not move as much air as it should when it needs to, thus can not help you control temps.

If it goes the other way and locks up all the time, something is wrong with it and while it won't hurt your temperatures, it has failed and needs replacement. Will make a lot of noise and is totally annoying. That's not as likely, but can happen.

 

[ELCAM]

the fan runs all the time, is that normal if it’s a thermal clutch ?

Thermal clutches generally came on heavy duty cooling option cars from the factory. They usually have a flat wound thermal spring on the front center of the clutch and are thick straight sided ( there are new ones that don't have the spring external). These are also about twice the price of a standard fan clutch so you don't see too many as replacements. It freewheels when it is cool and as it heats up it locks the fan blade to the water pump speed.

The standard fan clutch is a torque limiting type. Usually taper and are thin on the edges. It locks up at low speeds and begins to slip over something like 3000 RPM.

Very different parts. You need to know what you have though odds are it is the torque limiting type.

 

[69hurstolds]

Thermal clutches generally came on heavy duty cooling option cars from the factory. They usually have a flat wound thermal spring on the front center of the clutch ( there are new ones that don't have the spring external). These are also about twice the price of a standard fan clutch so you don't see too many as replacements. It freewheels when it is cool and as it heats up it locks the fan blade to the water pump speed.

The standard fan clutch is a torque limiting type. It locks up at low speeds and begins to slip over something like 3000 RPM.

Very different parts. You need to know what you have though odds are it is the torque limiting type.

These are good points, although I thought the OP stated he had a thermal clutch. Torque limiting is basically a break away. And yes, a torque limiting should run full speed from idle on up to upper highway cruising speed rpm.

All I've ever had is HD cooling with 442s and H/Os, so thermal fan clutches are standard in my life.

But yeah, you make a good point. KNOW which one you have for sure. Torque limiting kinda work backwards. Torque types use centrifugal force instead of temperature to control the fluid and that's to actually disable the fan at higher speeds.

Here's a good explanation of how a thermal fan clutch works-

 

[ELCAM]

These are good points, although I thought the OP stated he had a thermal clutch. Torque limiting is basically a break away. And yes, a torque limiting should run full speed from idle on up to upper highway cruising speed rpm.

All I've ever had is HD cooling with 442s and H/Os, so thermal fan clutches are standard in my life.

But yeah, you make a good point. KNOW which one you have for sure. Torque limiting kinda work backwards. Torque types use centrifugal force instead of temperature to control the fluid and that's to actually disable the fan at higher speeds.

Here's a good explanation of how a thermal fan clutch works-

Good info.

You spoil yourself with them high dollar cars.

The problem with the torque limited ones are they put a hurting on you at idle (ie. sitting in traffic) when they fail. The good ones usually fail in a noisy or leaky fashion.

 

[rubio9800]

my guess is that it’s a thermal, i would need to take it out. I can’t see the spring, but i felt around the clutch and felt what i think could be a spring

looking at Oreilly’s i see both options fit
thermal/non thermal

 

[69hurstolds]

The problem with the torque limited ones are they put a hurting on you at idle (ie. sitting in traffic) when they fail. The good ones usually fail in a noisy or leaky fashion.

Exactly the reason you need to know which type you have. If it's a thermal, it's ok if it spins easily by hand when cold. If it's Torque Limiting, and spins easily by hand when cold, it's bad.

 

[ELCAM]

my guess is that it’s a thermal, i would need to take it out. I can’t see the spring, but i felt around the clutch and felt what i think could be a spring

Your video shows a torque limited one. You can see the thin edge.

 

[69hurstolds]

my guess is that it’s a thermal, i would need to take it out. I can’t see the spring, but i felt around the clutch and felt what i think could be a spring

Once you get it out you'll be able to tell for sure. Of course, you can use either one with your fan blade and hub as they should bolt up the same. So even if you had a torque limiting and went with a thermal or vice-versa, it still should work. But if you have a thermal stock, I'd tend to stick with the thermal.

 

[rubio9800]

Once you get it out you'll be able to tell for sure. Of course, you can use either one with your fan blade and hub as they should bolt up the same. So even if you had a torque limiting and went with a thermal or vice-versa, it still should work. But if you have a thermal stock, I'd tend to stick with the thermal.

Your video shows a torque limited one. You can see the thin edge.

got it!

 

[rubio9800]

Once you get it out you'll be able to tell for sure. Of course, you can use either one with your fan blade and hub as they should bolt up the same. So even if you had a torque limiting and went with a thermal or vice-versa, it still should work. But if you have a thermal stock, I'd tend to stick with the thermal.

i don’t mind spending the few extra bucks for a thermal one