02-11-2006, 09:49 AM
|
#1
|
|
AF Newbie
Join Date: Sep 2005
Location: Birdsboro, Pennsylvania
Posts: 86
|
Another thing GM will call normal
Anyone have or can diagnose this problem?
When my truck is idling warm, every 20-30 seconds there will be this dull "thunk" that comes from somewhere on the truck. You can hear it and if you are totally still, feel it. It sounds like someone lightly punched the side of your truck through a pillow. I've gotten out before and crawled under it and heard it, but I have NO clue where it's coming from. It's loud enough you can hear it outside and inside of the truck, but it's not THAT loud. It almost sounds like something switching over, like for say the transfer case from 2wd to 4 but I never push anything! Anyone?
__________________
2001 Silverado 4x4 - 4.8 V8 BFG 265/75/R16 A/Ts
K&N FIPK - Ravin Muffler 3.5" Duals
4-Headlight Conversion Kit - Billet Grille
LED Line of Fire Bar - 90 Watt Nova Strobe Pack
Sirius Satellite Radio - Pioneer Head Unit
Pioneer 6 Disc CD Changer - 2.5% Limo Tint
Check Out Pictures and More Here
http://www.cardomain.com/ride/2131569/1
|
|
|
|
02-11-2006, 11:18 AM
|
#2
|
|
AF Newbie
Join Date: Aug 2005
Location: Avonmore, Pennsylvania
Posts: 58
|
Re: Another thing GM will call normal
I'd bet thet is the AC compressor cycling. The compressor will run when you have selected the defrost setting.
__________________
|
|
|
|
|
02-11-2006, 11:51 AM
|
#3
|
|
AF Newbie
Join Date: Sep 2005
Location: Birdsboro, Pennsylvania
Posts: 86
|
Re: Another thing GM will call normal
This happens with the defroster/fan etc.. all off. Nothing is running but the truck itself.
__________________
2001 Silverado 4x4 - 4.8 V8 BFG 265/75/R16 A/Ts
K&N FIPK - Ravin Muffler 3.5" Duals
4-Headlight Conversion Kit - Billet Grille
LED Line of Fire Bar - 90 Watt Nova Strobe Pack
Sirius Satellite Radio - Pioneer Head Unit
Pioneer 6 Disc CD Changer - 2.5% Limo Tint
Check Out Pictures and More Here
http://www.cardomain.com/ride/2131569/1
|
|
|
|
|
02-11-2006, 11:54 AM
|
#4
|
|
AF Newbie
Join Date: Nov 2005
Location: il, Illinois
Posts: 72
|
Re: Another thing GM will call normal
i have that same noise, don't know what the hell it is
|
|
|
|
|
02-11-2006, 11:59 AM
|
#5
|
|
AF Newbie
Join Date: Mar 2005
Location: western, Iowa
Posts: 55
|
Re: Another thing GM will call normal
get out and watch the compressor even when off I think the cycle, may be wrong though
|
|
|
|
|
02-11-2006, 06:33 PM
|
#6
|
|
AF Regular
Join Date: Dec 2005
Location: Centerport, New York
Posts: 103
|
Re: Another thing GM will call normal
I think my truck does the same thing. On most newer cars the A/C compressor cycles periodically to keep everything lubricated internally.
|
|
|
|
|
02-15-2006, 05:08 AM
|
#7
|
|
AF Regular
Join Date: Apr 2004
Location: Mt Pearl
Posts: 104
|
Re: Another thing GM will call normal
Yes the AC compressor will cycle on/off even without the AC turned on. I believe it does this as a sort of de-humidifier to reduce cab humidity and as so fogging of the windshield.
|
|
|
|
|
02-15-2006, 10:51 AM
|
#8
|
|
AF Regular
Join Date: Dec 2003
Location: jumping branch, West Virginia
Posts: 305
|
Re: Another thing GM will call normal
you described it as a thunk. I would take that description and suspect that ypou mayn be hearing the fuel tank expanding and the side of it thunking in or out . Perhaps pressure from recycling fuel build and then is release on a cycle? If you had said a tick or somthing then i would suspect somthing turning on or off but a thunk is something moving.
__________________
2000 Silverado Victory Red, standard cab, short bed, short wheelbase, 4X4, 4.8L, 5 speed, 4:10 locking rear diff, K&n FIPK, Ryno lined all the way over bed rail, heavy half suspension,factory skid plates,Fog lights, BFG 285/75/16 A/T's, dashmat, Stealth Radar.
lots of special options some installed by me!
1980 Suzuki GS1100E Super fast 
|
|
|
|
|
02-15-2006, 12:07 PM
|
#9
|
|
AF Regular
Join Date: Jan 2005
Location: Burleson, Texas
Posts: 206
|
Re: Another thing GM will call normal
My compressor also thunks, but I have never really checked to see if it does that when the ac is off.
__________________
2000 Silverado Ext.Cab, 5.3L, Pewter, True Flow Foam Filter, Airaid Intake, Flo-Pro Performance muffler, Hayden 679 Rapid Cool Transmission Cooler, Hidden Hitch
|
|
|
|
|
02-15-2006, 01:18 PM
|
#10
|
|
AF Newbie
Join Date: Feb 2006
Location: New Philadelphia, Ohio
Posts: 5
|
Re: Another thing GM will call normal
I've experienced something similar... exactly the way you've described... not only in my truck but in my car... I was told this is normal... go figure.
|
|
|
|
|
