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Fan Blades on backward?

aplatz

NAXJA Forum User
Location
Frederick, MD.
Finished my radiator, water pump project and eveything is nice and cool, but I have a pronounced "whirring" of my fan. Did I put my blades to my fan clutch on backward? I can't hear my engine growl when I step on it now. I just hear my fan. Engine temps are way cool now though.

Anybody know what's up w/ this?
 
I just took a quick look at mine and the smaller leading edges are towards the radiator and the wider edges are at the back towards the engine. If thats not clear let me know and I'll snap a pic.
 
Thanks, I'll check that....You'd think it would cause overheating if they were on backward. I also got lucky with radiators.com, they said they were shipping me a 2 core CSF w/ plastic tanks, but got the metal version.
 
Add this to the list of things when changing a fan clutch:
1-check the studs into the clutch. I had two walk out on me. Luckily, no damage other than my new schroud has a quarter size chunk taken out of it. Lasted a whole 12 miles! The mechanic had a cool socket that tightens the studs. Use red locktite too.
 
aplatz said:
Thanks, I'll check that....You'd think it would cause overheating if they were on backward. I also got lucky with radiators.com, they said they were shipping me a 2 core CSF w/ plastic tanks, but got the metal version.

Yes it would. The fan is supposed to "pull" air thru the radiator - if you spin it backwards, it will try to "push" air forward, which will cancel some/all of the "ram air" cooling you get from foward speed.

5-90
 
aplatz said:
Thanks, I'll check that....You'd think it would cause overheating if they were on backward. I also got lucky with radiators.com, they said they were shipping me a 2 core CSF w/ plastic tanks, but got the metal version.
The fan can't be backwards (no matter whtehter you flip it or not, it will always create movement of air in the same direction as long as you keep spinning it the same way)... you just might have the wrong fan if it's moving the air in the wrong direction (or you routed the belt wrong).
 
Kejtar said:
The fan can't be backwards (no matter whtehter you flip it or not, it will always create movement of air in the same direction as long as you keep spinning it the same way)... you just might have the wrong fan if it's moving the air in the wrong direction (or you routed the belt wrong).

Sure can be on backwards. May still pull but nowhere near as well as the right way. BTDT.

Sarge
 
Sarge said:
Sure can be on backwards. May still pull but nowhere near as well as the right way. BTDT.

Sarge
What I meant to say is that it will pull in the same direction if it's on backwards. If it pulls in the wrong direction then it's the wrong fan as the blades have the wrong slant on them.
 
If the fan is on backwards it will still pull air only not as much due to the design of the blades [smaller on one side, larger on the other]. The only way to get it to push air is to reverse it's direction of rotation. Even if you turn it around on the fan clutch it will still pull due to the direction of the fan blades.
You can demonstrate this with a cooling fan that has a removable blade on it's motor shaft.
I'd have to try it but with the smaller leading surface of the blade in the front it would move less air faster and the larger trailing portion would disperse it better. If it was reversed the lager leading edge would grab more air and it would accelerate as the trailing edge got smaller, think, might have it backwards, boyles law used to give me fits too...
Trying to think of the word where both edges of the fan are different, asomething, like where one side of your face does not match the other and you features are consided asomething, damn, hate when I got it on the tip of my tounge... don't mind me I'm trying to free associate... I'll remember it about 15 min after I hit submit....
 
RichP said:
I just took a quick look at mine and the smaller leading edges are towards the radiator and the wider edges are at the back towards the engine. If thats not clear let me know and I'll snap a pic.

Sorry for the hijack but by this do you mean that the side with the curved edge and shorter straight surface should be closer to the radiator and the other side with the whole side thats straight should be towards the engine?

I just wanted to make sure mine is on right.
Thanks :D
 
RichP said:
Trying to think of the word where both edges of the fan are different, asomething, like where one side of your face does not match the other and you features are consided asomething, damn, hate when I got it on the tip of my tounge... don't mind me I'm trying to free associate... I'll remember it about 15 min after I hit submit....


Asymmetric the word you were huntin for?
 
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