Electric Fan Clearance

[OLKY55]

I thought I had my cooling issue solved with my new PRC cross-flow and dual 13" fans, but I was having a problem with the right side electric fan expanding when it warms up and pushing against the front of the AC compressor clutch. I figured I would be okay as long as I didn't turn on the AC, but it was also pushing the fan shaft into my radiator. I now have a fan-motor shaft sized hole in my new radiator. How much clearance do you need from the rear of an electric fan? I'm thinking 1/16" is maybe not enough.

[chevynut]

Well whatever you had obviously wasn't enough.

What fans are you using? Don't they have an integral shroud like the Spal or Derale fans?

[OLKY55]

They're Spal fans, with a plastic shroud. I think I have more than one problem. Beside the fan expansion issue, it looks like my driveshaft is too long and that is shoving the engine forward into the fan, and the fan into the radiator.

[chevynut]

Personally I have a hard time seeing how fans can "expand". How is your engine hitting the fans?

[OLKY55]

I had a hard time believing it until I saw it. When the engine was cold, I could slide a 1/16 sheet of aluminum between the fan and the A/C compressor. I figured as long as it wasn't touching, right? After driving a few miles and warming it up to operating temperature, I checked it again to make sure it was okay and the fan was jammed up against the compressor. Fortunately, the A/C wasn't on. It is hard to say how much everything grew, but it was pressing against it pretty hard.

I don't think that is what caused the fan to also get into the radiator, but I'm trying to allow for enough clearance when I put everything back together.

[chevynut]

Of course plastic can expand, but it's amazing it can get hot enough to expand that much if that's really what's happening. Hope you're able to gain some clearance somehow.

[Rick_L]

A puller fan is going to have a thrust force toward the radiator and the fan will move toward the radiator if the mount is not stiff enough. The force is simply the pressure developed by the fan times the area of the fan blades.

I doubt if it's that simple but it's something to think about.