Fan Rattle?

John Borland

Junior Member
I have an intermediate (occurs off an on every 15 seconds or so) rattling noise that I think may be from my fan belt not being exactly aligned with the engine fan pulley (it is about a 1/2" further away from the radiator at the fan pulley compared to the alternator pulley).

A couple months ago, I had a more consistent noise from the fan blade not being tight enough. I took the fan off inspected it, and then re-installed it more tightly. The fan seems to be still tight, though I can slightly jingle the outer ends of the fan by hand. Any help in further diagnosing (before I order in a new fan) would be greatly appreciated.

Thanks,
John
 
what kind of fan? original 2 blade steel? maybe its coming apart
if it is get the 2 blade aluminun those old blades are a time bomb and can decapitate ya
 
It's an aluminum 2 blade fan. I checked the fan for cracks when I had it off and found none. I'm thinking that maybe I tighten it too much. Guess I will take the fan belt off and see if the noise goes away. Problem being is that the noise is not consistent.
 
It's an aluminum 2 blade fan. I checked the fan for cracks when I had it off and found none. I'm thinking that maybe I tighten it too much. Guess I will take the fan belt off and see if the noise goes away. Problem being is that the noise is not consistent.

How old is it? I have read the taper was wrong on some of the early aluminum two blade fans.
 
I had a new aluminum fan that would not stay tight. It turns out that the taper on the water pump shaft was incorrect. I ended up buying another two blade fan and a new leakless water pump. I have not had the problem since.
 
How old is it? I have read the taper was wrong on some of the early aluminum two blade fans.

In addition it is recommended to install a thin steel washer under the retainer nut, I also removed the powder coating from where the nut fits, I don't believe the fans sold from the vendors have had any problems in the last few years.
 
when you wobble the fan blade is it moving independent of the pump shaft at the nut or as a unit...

this can help you determine if its a pump or not..
 
Pulley Alignment:

A yard stick or a similar straight edge positioned on diameters or radians of two (2) adjacent pulleys can be used to check pulley alignment between two (2) adjacent pulleys.

The straight edge should contact the two (2) outer circumferences of the two (2) adjacent pulleys at all four (4) outer circumference locations when the two (2) pulleys are properly aligned.
 
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