Harmonic Balancer on 2007
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3rd Gear
Joined: Jul 2021
Posts: 3
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Harmonic Balancer on 2007
Had to have this replaced 6 months ago. It's back at the dealer due to the new H.B. looking like it's going to fly off. I read that there was a technical bulletin issued back in the c6 era that warned of the H.B. bolt backing itself out. Does anyone know what Chevy's fix was for that? It makes me uneasy knowing that I only drove it 500 miles and it's back in the shop for this. Thanks in advance..
Le Mans Master
Joined: Dec 2004
Posts: 5,492
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From: West coast CA
Had to have this replaced 6 months ago. It's back at the dealer due to the new H.B. looking like it's going to fly off. I read that there was a technical bulletin issued back in the c6 era that warned of the H.B. bolt backing itself out. Does anyone know what Chevy's fix was for that? It makes me uneasy knowing that I only drove it 500 miles and it's back in the shop for this. Thanks in advance..
1) The bolt loosens and the entire balancer assembly walks off the crank. This plagued early-production C6s and was addressed by the addition of a thin diamond-encrusted washer behind the balancer. The torque sequence is a pain and the factory TTY bolt cannot be reused. If your bolt came loose the most likely cause was improper installation.
2) The balancer itself comes apart, and the pulley section separates from the hub. The bolt remains tight. If this happened to you, the cause is a defective part.
Instructor
Joined: May 2023
Posts: 217
Likes: 95
I bought a 06 Z51 with the harmonic balancer changed by the previous owner. After a hard day at the track, the bolt came lose and they used a stock flawed replacement balancer. SFI balancer is now installed with an ARP bolt to have peace of mind. Never use the oem junk balancers when changing them,
