I6 fan operation

signalnc

Original poster
Member
Dec 28, 2012
249
Can anyone tell me how the fan is supposed to operate on an 4.2 I6? when I start my wifes 2003 TB it sounds like an airplane, then it goes away after a few minutes of warming up , or it goes away after you start driving. Is that normal? thanks.
I just don't quite understand how it is supposed to work. I'm thinking it has a clutch in there and the computer tells it to engage to produce more air flow.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
That's sort of normal operation, but as the pre-2005 fan clutches age, they can get noisier and noisier until they stay engaged all the time and sound like an F16 on afterburner. Many, many discussions about replacing them and getting a PCM update from the dealer to fix the reliability issue and improve AC operation on start-up in hot weather.

For more reading, trailvoy had the definitive threads:

Fan clutch 101 - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum
service bulletin# 060602003 - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

And here's a couple of useful documents:

<dead link>[PDF]http://www.roadie.org/TechlinkEVClutch.pdf[/PDF]
Another source: http://www.norcal-cobras.com/GTM/gm-tech-link/7_02_e.pdf

<dead link>[PDF]http://www.roadie.org/fanclutchalldata.pdf[/PDF]
 
Last edited by a moderator:

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
signalnc said:
Can anyone tell me how the fan is supposed to operate on an 4.2 I6? when I start my wifes 2003 TB it sounds like an airplane, then it goes away after a few minutes of warming up , or it goes away after you start driving. Is that normal? thanks. I just don't quite understand how it is supposed to work. I'm thinking it has a clutch in there and the computer tells it to engage to produce more air flow.

The sound at start-up is not unusual. As long as it goes away, it's fine. Also, yes, that's how the fan clutch works.

Damn, I knew I should not have gone for coffee. :duh:
Nice new info, Roadie. :thumbsup:
 

Forum Statistics

Threads
23,392
Posts
638,780
Members
18,601
Latest member
Chris Moore

Members Online