Crank cooling fan?!?

Maybe I need to be educated, but why did Toyota put a fun directly connected to the crank instead of an electric one?

Mechanical fan connected to crank pulley instead of electric fan attached to radiator.

Doesn't that need more energy from the engine to turn the crank (with fan) resulting in using more fuel?

I'm not a mechanic so maybe there is a super simple explanation. Cost maybe.

I am just curious here and I am trying to understand.

 

What the... Crank fan? What dat boi talking about...

 

Mechanical fan connected to crank pulley instead of electric fan attached to radiator.
Sorry for the bad explanation! lol. Damn frenchy here! lol

 

Not a picture from the Tacoma engine, but just as an example to show what I am talking about!

 

Are you sure that isn't run off the serpentine belt? There must be something between the fan and the crank in the event of a failure.

 

Maybe! I'll have to look later.
But my question is (even if it's run by the serpentine belt); why go with this instead of electrical fan?

 

Well first off, I should point out that the most important part of cooling is if the blades and shroud are designed properly. Without that, you can't cool very well with any kind of fan.

Mechanical does involve a reasonable bit of parasitic loss, but I do believe the cost is probably a big consideration. All else being equal, 1 mechanical fan is going to cool better than 1 electrical fan.

Also, the mechanical fan does have a clutch that allows it to be less of a drain, and it can be continuously turning while the engine is running. Electrical is usually on or off.

Electrical does have a lot of advantages (size and mounting flexibility, no parasitic HP loss) so I'm looking forward to seeing what the aftermarket comes up with for the 3rd gen Tacos.

 

Cool thanks for the info!!

 

All I know is that my dual electric fans are giving me overheating issues in certain coditions such as slow speeds in 4x4 with the AC on. With the stock clutch fan I never had that happen. Electric fans seem to be less reliable for optimal cooling under high load scenarios IMO.

 

Turning mechanical energy into 13 volt electricity and then using that electricity to turn a fan motor has it's losses, too. Anything with a large load at 13 volts is going to be quite lossy.

 

Thanks for the info guys!
Always good to learn new stuff!

 

I am sure, the silver thing in the middle of the clutch with cooling fins attached is a clutch, allowing the fan to be disconnected when not needed and the clutch engages when the fan is needed. Electric fan would absolutely draw less power from the motor freeing up more power for acceleration. Why Toyota didn't make one? I have to assume cost was the only factor as usual.

 

Did you reuse the factory shroud or use one that came with the fan? And where are you picking up temperature for the fan from?

 

Nitori hit the nail on the head, a mechanical fan (crank mounted, water pump mounted) moves a higher volume of air when coupled with the proper fan shroud (black plastic piece covering the sides of the radiator core). This is advantageous in low speed, high load, and towing situations.

The clutch (silver disk in the middle of the fan) can control how fast the fan blades spin (how much air it pulls through the radiator core) based on the temp of the fluid within it and engine speed.

Toyota probably stuck with the mechanical fan due to the fact that its cheaper, simpler, and works very well in a wide range of conditions. That's my .02.

 

Fan clutch is simpler and more reliable for most applications especially for trucks. The clutch is supposed to have minimal parasitic loss when not fully engaged.

 

Clutch Fan is best on this type of vehicle. Notice how the blades are nice and steep and big compared to electric fans, which allow more airflow at lower RPMs with less noise, and a lot more airflow at higher RpM. Plus that reliability.

 

Sound really nice when turning at max speed too. Like a fighter jet taking off.

 

Mechanical, if engines on, fan is on. Less chance of failure.
Mechanical, as engine load increases, cooling increases.
Electric, is on or off, additional relays, thermostats and sensors which all have dramatically less life than a chunk of metal.
Electric, as engine load increases, cooling ability doesn't increase. Which is fine on a small car, but a truck that may tow things needs ability to ramp up cooling when loaded. Or the electric motor would have to be so big that cooling under normal daily driver conditions would be wasting electric power and probably incapable of being run by just an alternator's output.

I just wish they would go with the flexible blade type of fans instead of the clutch'ed bs. Would eliminate another failure point, the clutch.

 

Flex fan would overcool and increase drag significantly.

 

I 100% agree there! Loved that about my old 02 4runner as well!