Crank pully wobble
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Joined: Feb 2011
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Crank pully wobble
I have read its common on 05 years where the bolt starts to loosen up. I have a slight wobble right now. I am going to be getting it fixed in a month or two with new pully, new bolt and friction washer. I can't help but think am I going to do any damage or put more wear on the motor with it like that? It is only a mild wobble but will this put more pressure on the crank and cause bearing wear or am I safe to drive the car unless the wobble gets worse?
Thanks
Thanks
Le Mans Master
Joined: Nov 2007
Posts: 6,412
Likes: 198
From: Wilkes-Barre Pa
If its coming loose tighten it immediately.
What happens is the pulley comes loose then starts slipping which will damage the end of the crank. If the shaft gets damaged its to late for a new pulley and bolt.
What happens is the pulley comes loose then starts slipping which will damage the end of the crank. If the shaft gets damaged its to late for a new pulley and bolt.
Race Director
Joined: Jun 2005
Posts: 10,908
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From: Phila Suburbs 2023 C8 & 2013 650ix
Slight pulley wobble is NORMAL. If you don't have an early 05 then bolt loosening is NOT a problem you should be NOT be concerned about it. If your belt is not chirping, NO ACTION IS REQUIRED. A pulley that is wobbling enough to cause chirping and needs replacement will NOT hurt the engine.
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I am a bit confused by some of the responses. I DO have a 05 not sure if it's "early" or not. It is also a Z51. There is a slight wobble and chirp and if you watch the tensioner it bobbs up and down due to the crank pully. It's not loose as in the bolt coming out but I predict it's loose because the 05 had this problem and there was a service bulletin on it that is suppose to be why it gets the wobble. According to the shop and my estimates you need to take the whole front end of the car apart to change the pully or gain access to the bolt unless there is a special tool. I can get a socket on it but there is absolutely no room if it is connected to a ratchet.
Pro
Joined: Apr 2009
Posts: 581
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From: NJ
I am a bit confused by some of the responses. I DO have a 05 not sure if it's "early" or not. It is also a Z51. There is a slight wobble and chirp and if you watch the tensioner it bobbs up and down due to the crank pully. It's not loose as in the bolt coming out but I predict it's loose because the 05 had this problem and there was a service bulletin on it that is suppose to be why it gets the wobble. According to the shop and my estimates you need to take the whole front end of the car apart to change the pully or gain access to the bolt unless there is a special tool. I can get a socket on it but there is absolutely no room if it is connected to a ratchet.
So, to be on the safe side and save yourself money, get it pinned ASAP. Should be about 3-4 hours of labor, a NEW bolt, and a pin kit. A wobbly pulley will throw everything out of whack if not straight, as it did to my water pump and alternator.
Race Director
Joined: Jun 2005
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From: Phila Suburbs 2023 C8 & 2013 650ix
The "loose bolt" in 05's was "suspected" in the first 11039 cars. Your VINs last 5 numbers tells you if you are in the affected range. You are right the GM procedure calls for a lot of front end disassembly to replace it and it's about a $1000 job. Others have said it can be done without all the disassembly and cheaper. If the belt is chirping, the only cure is to replace the crank pulley (harmonic balancer). A wobble can occur with a loose bolt but once the bolt is actually loose it's a short trip to the pulley flying off. More likely it's a failed rubber flexible coupling in the crank pulley that is causing the pulley to wobble and the belt to chirp.
Race Director
Joined: Mar 2007
Posts: 11,331
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From: Missouri City Texas
The "loose bolt" in 05's was "suspected" in the first 11039 cars. Your VINs last 5 numbers tells you if you are in the affected range. You are right the GM procedure calls for a lot of front end disassembly to replace it and it's about a $1000 job. Others have said it can be done without all the disassembly and cheaper.
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Tolero Apto Victum
Joined: Jul 2007
Posts: 9,669
Likes: 37
From: Woodlands TX
I had the wobblies on my 07, took it to Corvettes of Houston and had it replaced with one from ATI http://www.atiracing.com/products/da...ts/damserp.htm
Good Luck!
Good Luck!
Thread Starter
Advanced
Joined: Feb 2011
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How is that possible? Do they have some type of magic trick where they can pull it off even though the front steering rack is blocking it in? Thats amazing! My local dealer also says it's $1000 labor because you have to remove steering rack and other things. If there is some magic trick im sure everyone wants to know how it is done 
Pro
Joined: Apr 2009
Posts: 581
Likes: 10
From: NJ
How is that possible? Do they have some type of magic trick where they can pull it off even though the front steering rack is blocking it in? Thats amazing! My local dealer also says it's $1000 labor because you have to remove steering rack and other things. If there is some magic trick im sure everyone wants to know how it is done
Not sure where you are located but if you are out of warranty, I recommend you find a trustworthy mechanic/shop to work on your car. Luckily for me, ecs is only 25mins away and they are the only ones who I let work on my car.
Advanced
Joined: Jan 2008
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From: Oceanside Kalifornia
I have the wobble on my 07. Is this sort of thing covered by the 07 and up power train warranty? I am within the 5yr/100k mile limits of the powertrain warranty they offered starting that year.
Intermediate
Joined: Sep 2009
Posts: 32
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From: Ostrander Ohio
C6 Crank Pulley
I have a 2011 Grand Sport and the pulley is moving enough to make the belt chirp. it is visibly wiggling. Being under warranty is a good thing, but I hope the shop can accomplish whatever repairs are necessary without taking half the summer!
By the way on my LS3 the pulley bolt head is 15/16, but it's impossible to get both the socket and handle in there.
By the way on my LS3 the pulley bolt head is 15/16, but it's impossible to get both the socket and handle in there.
Pro
Joined: Aug 2010
Posts: 748
Likes: 3
Slight pulley wobble is NORMAL. If you don't have an early 05 then bolt loosening is NOT a problem you should be NOT be concerned about it. If your belt is not chirping, NO ACTION IS REQUIRED. A pulley that is wobbling enough to cause chirping and needs replacement will NOT hurt the engine.
I put on a brand new OEM pulley to fix the wobbling, it was dead straight. No runout at all. Then within a month the replacement failed as well.
I switched to an expensive ATI harmonic balancer and it has been perfect for almost a year now. And I'll never have to worry about it again.
Get rid of that OEM piece of junk !
Instructor
Joined: Sep 2011
Posts: 231
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From: Chester County PA
