Radiator fan direction

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

George915

Junior Member
Joined
Jan 21, 2023
Posts
18
Reaction score
23
Location
parma ohio
First Name
George
Truck Year
1984
Truck Model
K10
Engine Size
307
I’m in the process of an Engine swap on my 1984 K10 , first time under taking an engine swap before. Decided to replace the clutch on the fan as well as give the fan a fresh coat of paint. I just want to be sure I’m putting the fan back on in the right direction. Does the Front stamp on the fan face the engine or face the clutch Any help would be appreciated. I couldn’t find anything in the shop manual. Thanks
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
165
Reaction score
193
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
I’m in the process of an Engine swap on my 1984 K10 , first time under taking an engine swap before. Decided to replace the clutch on the fan as well as give the fan a fresh coat of paint. I just want to be sure I’m putting the fan back on in the right direction. Does the Front stamp on the fan face the engine or face the clutch Any help would be appreciated. I couldn’t find anything in the shop manual. Thanks

Also when rotating it should blow air towards the engine, sucking through the radiator. It should be pretty easy to tell based on the rotation and angle of the blades, but don't tell that to the previous owners of my 1989 who had it blowing the wrong way.....
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,456
Reaction score
8,716
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Also when rotating it should blow air towards the engine, sucking through the radiator. It should be pretty easy to tell based on the rotation and angle of the blades, but don't tell that to the previous owners of my 1989 who had it blowing the wrong way.....
The pitch off the fan blade doesn't change if you flip it, either way it still pulls air to the engine. If it's not pulling towards the engine,you have the wrong fan for your accesorie drive. And a tidbit for anyone that may need to know. If you look at the back of a factory fan assembly. Order is hub with flanges and rivets,blades riveted to hub, then clutch in the front.
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
165
Reaction score
193
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
The pitch off the fan blade doesn't change if you flip it, either way it still pulls air to the engine. If it's not pulling towards the engine,you have the wrong fan for your accesorie drive. And a tidbit for anyone that may need to know. If you look at the back of a factory fan assembly. Order is hub with flanges and rivets,blades riveted to hub, then clutch in the front.

Yeah - I found that out the hard way when I went to flip it around thinking they had put it on backwards, and it was STILL wrong. Had to go buy the right fan, they apparently put one from an older engine that used V belts (pump turning same direction as engine) instead of a serpentine setup where the pump turns opposite of the engine. New fan and new clutch later and it stays sort of cool now except when in traffic.
 

Ricko1966

Full Access Member
Joined
Apr 11, 2017
Posts
5,456
Reaction score
8,716
Location
kansas
First Name
Rick
Truck Year
1975
Truck Model
c20
Engine Size
350
Yeah - I found that out the hard way when I went to flip it around thinking they had put it on backwards, and it was STILL wrong. Had to go buy the right fan, they apparently put one from an older engine that used V belts (pump turning same direction as engine) instead of a serpentine setup where the pump turns opposite of the engine. New fan and new clutch later and it stays sort of cool now except when in traffic.
There's more to it than that. All serpentine belts don't reverse rotate the fan and water pump. And all water pumps aren't meant to rotate the same direction. If your water pump is turning counter clockwise,you need to be sure you have a waterpump designed to rotate counter clockwise.
 

YakkoWarner

Full Access Member
Joined
May 29, 2024
Posts
165
Reaction score
193
Location
Central Texas
First Name
Wolf
Truck Year
1989
Truck Model
R2500 Suburban
Engine Size
454
There's more to it than that. All serpentine belts don't reverse rotate the fan and water pump. And all water pumps aren't meant to rotate the same direction. If your water pump is turning counter clockwise,you need to be sure you have a waterpump designed to rotate counter clockwise.

Unfortunately I couldn't find any markings on it that would indicate which direction it should turn, so I had to go more or less on faith that it was the correct pump for the engine (and it did not appear to be a recent replacement) - it stays perfectly cool running down the highway at 67-70. It had the correct direction clutch but since I was replacing the fan I figured it was just as easy to do both. I figure someone bent the fan and bought a new one without paying attention to the rotation.
 

Forum statistics

Threads
44,175
Posts
950,931
Members
36,299
Latest member
gman64
Top