FAN CLUTCH FAQ's

[Jack]

The subject of when to replace a fan clutch has come up more than a few times. As I perused the Hayden (manufacturer) site http://www.haydenauto.com/faq.html I found a great deal of info; a bit of which I've gone ahead & posted.

FAN CLUTCHES
Q. How do I know if my fan clutch needs to be replaced?
A. These are the most common symptoms of a failed fan clutch:
• Leaking fluid - Oily build up around the bearing or thermal spring.
• Bad bearing - Seized, turns rough or has excessive play (more than 1/4" at fan tip).
• Worn thermal spring - Spring is loose.


Some fan clutches will show no visible indication of a problem yet may still be faulty. The following may also indicate a faulty fan clutch:
• Fan spins excessively - Three or more times when hot engine is shut off.
• Poor air conditioning - At low speed or excessive high side pressures.
• Doesn't engage - Fan speed does not increase or "locks up" when the engine is hot.
• Does not disengage - Fan clutch won't slow down when the engine is cold.

JACK:gap

 

[Moffitt]

Don't forget:
Fan clutch not matched to fan diameter and pitch (does not disengage).
This happens most with aftermarket fan clutches being sold by "it will fit" instead of "this is the correct one".
OEM is a sure thing, if it's still to be found.
Beware some clutches are not real clutches, the are just a viscus coupling, sometimes called "torque limiting"

 

[Jack]

one-size-fits-all ... NOT

Quite true Moffitt!!!! FYI ... in addition to further info on fc do's & don'ts and how the different types of fc's work, the Hayden link above has another link to catalog that includes specs & dimensions of darn near every fc & fan blade imaginable. BTW, Hayden's email tech support is very responsive .
JACK:gap