Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 9 of 9 Posts

·
Registered
2003 chevy trailblazer_ls_ext
Joined
·
15 Posts
Discussion Starter · #1 ·
I am a brandnew memeber to this site. I have an 03 Trailblazer and I hvae been reading about I problem I have. Let me start by saying these have been some excellent articles. I started hearing the dreaded ticking sound about a year ago and did not think much of it. Now I have the dreaed ROARING come from under the hood until I hit about 35mph. I have read enough to know that my fan clutch is toast. Which sucks because when I first heard the roaring I checked the fan and it moved latterally which told me my water pump was about to go, so I changed it out. But, you guessed it I did not replace the clutch while it was out "STUPID". I did not know then what I know now.

I have read about having to have the "software flashed" once this is complete? Can someone help me out with this. I dont really understand what is going on. Is it something that has to be done? Can I do it myself? Will the dealer do it after I replaced the clutch myself. Again thanks for any help you can provide and if there are any special tricks to removing the clutch from the fan caould you let me know.Thanks again

Ed
 

·
Registered
2003 chevy trailblazer_lt_ext
Joined
·
967 Posts
Flashing any onboard computers is not required for replacement of the fan clutch. Just install the new clutch and enjoy a quieter truck! :)
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
the software update can only be done by the dealer.
it is not required when you do the fan clutch change.

those that have the update- do it mostly to improve the operation of the AC when theyre at Idle and or in slow moving situations.

one of the things the software does is change how much air the fan pulls when its idling--- in this case it pulls more air- and makes the AC operate better in these conditions.....
 

·
Registered
2005 chevy trailblazer_ls_ext
Joined
·
2,667 Posts
:iagree: with Rbarrios. It's not necessary to have the software updated but I would have it done.

Unfortunately most people have reported it usually runs around 100 bucks at the stealerships, uh I mean dealership! :D
 

·
Registered
2003 chevy trailblazer_ls_ext
Joined
·
15 Posts
Discussion Starter · #5 ·
Thanks

Appreciate the info! Is there any special procedure for removing the clutch from the fan? Did anyone else have to cut the shroud to get it around the upper radiator outlet nipple?
 

·
Registered
2003 gmc envoy_slt
Joined
·
1 Posts
Yes I had to cut mine. It made it alot easier getting it out and then back in. I then found a small piece of plastic and fastened it back over the cut. Now when I first start the voy it still has that wooshing sound, but then idles down to normal. I do need to change my water pump now. I noticed yesterday that a noise was coming from that same area, so I grabbed a hold of the fan and it moves laterally.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
check your serpentine belt also- the wobble of the fan can cause the wearing of the belt on the sides as it rubs on the pulleys
 

·
Registered
2004 chevy trailblazer_lt
Joined
·
107 Posts
So when you update your software at a dealer, I understand that it helps the AC operate better/more effectively, but does it give you the loud roar when you first start the truck up and drive for a while?
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
5,268 Posts
the loud roar is normal upon startup. But I dont think its tied to the Software
dependant on vehicle and temp...

the roar occurs after the vehicle has been sitting for a while.. normally overnight....
1st thing in the morning- it roars- and then quiets down.
some of us report different amounts of time.
I being in So CAL where its not too cold- the roar last for about 20 seconds.
others report a few minutes.
some say it remains for a bit while they drive.
if it last excessively long- then time to look into it.
 
1 - 9 of 9 Posts
Top