Fan/Radiator Clearance

[Dibbons]

Everyone has their own opinion (may be talking about plastic fan flex, not the same with a fixed metal fan). Two from internet search:

Shoot for about 1/2"-3/4" clearance from fan to radiator. The very important shroud should have 2/3 of the fan inside the shroud and 1/3 of the fan outside the shroud.

The last measurement you should check is the distance from the face of the fan to the radiator. There should be at least 1 inch of clearance between the two. This is to accommodate normal engine and radiator movement, and also the flex that occurs in the fan blades at higher engine rpm.

 

[khryslerkid]

If you're not using a shroud they like to shoot for the closer measurement. I wouldn't like 1/2".

When using a shroud this is the correct formula to have 1/3 out of the shroud. The distance from the rad to the fan isn't important as long as the fan isn't too close.

Engine movement comes into play when the fan is too close as much as fan flex. There was a thread on here with a member having fan interference from engine movement.

 

[Dibbons]

I measured the crank pulley at 24" circumference while the fan/water pump pulley is at 19". Therefore, I figure the fan/water pump is running at a slight overdrive. No question here, just analyzing the parameters of the cooling system. Don't know if we have factory pulleys here and neither am I informed on how factory installation pulley rations varied model to model and year to year (standard vs heavy duty vs A/C).

https://www.hotrod.com/articles/pull/