Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 6 of 6 Posts

·
Registered
2006 gmc envoy_sle
Joined
·
15 Posts
Discussion Starter · #1 ·
I own a 2006 Envoy with the 4.2. I replaced my idler bearing and waterpump because of noisy bearings. The cooling fan has always had a wobble to it, even more pronounced at idle. To correct this I decided to replace the fan clutch in light of all the problems I am reading about these units assuming the bearing is going. Replaced the unit and the fan still wobbles . At start up the fan clutch engages, and the fan rotates smoothly.... it disengages after a minute or so and the fan begins to wobble. Out of frustration and several postings on this website I decide to replace the fan itself because the original one seems out of round when you spin it by hand. Installed the new one and the same senario.....fan engaged it rotates perfectly. After a short period of time it slows down and you can see the fan engaging and disengaging going from smooth to wobbling while its doing this. Eventually at engine idle it stays wobbling. It appears to be moving back and forth about 1/4 to 1/2" while turning.
Any solutions to this or is this considered normal. This is driving me crazy !!
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
the wobble were accustomes to seeing is caused because the shaft that the fan clutch attaches to--- is loose..
the shaft is the water pump shaft-- its bearings are beginning to fail.
did you check to make sure the shaft has NO movement- except rotational?
 

·
Registered
2004 gmc envoy_sle
Joined
·
399 Posts
If you replaced the water pump, then bearings are out of the equation. Mine appears to wobble also, but does not. Does yours have the plastic shroud around the blades like mine? If so, I believe it just appears that way, but is actually fine. If something was bad or out of balance, you would probably notice a vibration when the fan is fully engaged.:m2:
 

·
Banned
2003 gmc envoy_slt
Joined
·
7,190 Posts
With the engine off, line up a ruler on a fixed point and turn the fan by hand. You should be able to see if the fan is warped and by how much.:m2:
 

·
Registered
2005 chevy trailblazer_ls
Joined
·
607 Posts
If you replaced the water pump, then bearings are out of the equation. Mine appears to wobble also, but does not. Does yours have the plastic shroud around the blades like mine? If so, I believe it just appears that way, but is actually fine. If something was bad or out of balance, you would probably notice a vibration when the fan is fully engaged.:m2:
:iagree: On mine, the fan blades themselves are perfect, but the ring around them appears to wobble like crazy. When it's off, try to move the fan from the sides. It should not move more than about 1/4 - 1/2".
 

·
Registered
2006 gmc envoy_sle
Joined
·
15 Posts
Discussion Starter · #6 ·
Thanks for all of your replys. As I have noted I have replaced everything and when the engine is off I can grab the fan on both sides and move it back and forth about 1/4 ". All fan clutches with the fans attached seem to be like this. I have compared this to my inlaws Trailblazer and it appears to be the same. The water pump bearing is solid with no play in it. I thought the fan would wobble the most when it is engaged but this is when it rotates the smoothest. My original fan outer ring had some distortion in it so that is why I decided for a new one. The shaft on the fan clutch attached to the water pump turns perfect with no imbalance.....the wobble is only in the plastic fan itself.Fortunately myself and a mechanic friend have done all of the repairs so it has only cost me the parts.
Do all 4.2 engines have this movement in the fan ?
 
1 - 6 of 6 Posts
Top