surburban99

I am a little confused about what numbers of the VIN fall under the potential problem of the crank bolt. Do you look at the last six digits of the VIN?

Here is the VIN of the C6 I am considering:

1G1YY24UX55121416

Does this VIN fall under this range?

Thanks for your help!!

MThomas

No that vin does not fall within the range. You should be safe.

Datawiz

The last 5 digits of your vin need to be less than 11039 to be in the range.

surburban99

Thanks for the help!!

Steve Lutfy

So, if the last 5 digits of my VIN is 10640, are you saying that I'll probably have problems with my crank bolt pulley? I'm a little confused.

Thanks
Steve

Miaugi

That is what he is saying. Sorry but you are in the range, BTW, so am I!

VNAMVET

Mine is 10035.......11/04 build date and at 2600 miles..........KABOOM!!

You REALLY need to have it torqued to specs.................it's going to happen.................when you least expect it.

lemansbc6

si im assuming im in this range with a vin with the last 5 digits 05039..what is GM doing to correct this...if anything??? what is everyone doing if you fall in the range...bring your car to the dealer to correct the tourque specs??? what is the aftermath of this happening???

Steve Lutfy

Does anyone know if GM issued a Service Bulletin regarding this problem? If not, I'm sure it won't be easy to convince a dealer to fix something that they really don't know much about.

Datawiz

Yes, you're in the range. Individual dealers have chosen to do the repair proactively, but most do not. Pay attention to the noises in your engine bay. I caught mine in the garage.....thankfully.

Datawiz

Depends on the dealer and your relationship with them. Hopefully, GM will be taking a new approach on this issue.

Here is the TSB.

I've copied the TSA fix that C-5 TECH posted yesterday on how the fix it.
Here is the latest released 2/8/05...sorry,no pics

Check Gages Light, Battery Voltage Low, Accessory Drive Belt Slipping or Missing (Install Washer from WPC and Crankshaft Balancer) #05-06-01-001A - (Feb 8, 2005)
Table 1: Warranty Parts Center Parts
Table 2: GMSPO Parts
Table 3: Part Request Form -- Warranty Parts Center
Check Gages Light, Battery Voltage Low, Accessory Drive Belt Slipping or Missing (Install Washer from WPC and Crankshaft Balancer)
2005 Chevrolet Corvette

with 6.0L Engine (VIN U - RPO LS2)

Built Prior to VIN Breakpoint 55111039

This bulletin is being revised to include VIN breakpoint and additional inspection information. Please discard Corporate Bulletin Number 05-06-01-001 (Section 6 -- Engine).

Condition
Some customers may comment on the Check Gages Light or the Battery Voltage Low indicator coming on. Additionally, some customers may comment on the accessory drive belt either slipping or being missing.

Cause
The crankshaft balancer bolt may have become loose.

Correction
Install a new crankshaft balancer pulley, washer and a new balancer pulley bolt using the following procedure:

Disconnect the negative battery cable at the battery.



Remove the air duct (6).



Remove the radiator support.



Remove the accessory drive belt.



Disconnect the generator.



Remove the generator bolts and generator.



Disconnect the steering intermediate shaft at the steering gear.
Install the lifting links to the engine (J 41798).
Install the fixture for lifting the engine (J 41803).
Hoist the vehicle.
Remove the front wheels.
Loosen the motor mounts.



Install the leaf spring fixture (J 33432-A).



Disconnect the tie rods (5) from the steering knuckle (4).
Disconnect the speed sensor.



Remove the lower ball joint nut and disconnect the lower control arm from the knuckle.
Disconnect the bottom shock absorber bolts.
Disconnect the ABS module bracket bolts.



Disconnect the stabilizer shaft insulator clamp bracket bolts and shaft.
Disconnect the cooler line bolts to the engine cradle.
Install a suitable jack under the cradle.
Remove the cradle nuts.
Lower the cradle.



Remove the A/C belt.



Disconnect and remove the starter.



Install the flywheel holding fixture J 42386-A.



Remove the cooling fan bolts and fan assembly.



Scribe or mark balancer orientation.



Remove the crankshaft balancer bolt (139). Do not discard the crankshaft balancer bolt. The balancer bolt will be used during the balancer installation procedure.



Use the J 41816 (1) and the J 41816-2 (2) in order to remove the crankshaft balancer.
Place the old and new balancers on the bench and orient them the same way (i.e. face up with a weight balance hole at 12 o'clock). Scribe/mark the new balancer in the same location as the old balancer. Do not transfer weight pins on manual transmission equipped vehicles. Most vehicles will be balanced without the use of any additional weight pins. Because some balancers may have spun on the crankshaft, transferring weight pins to the same position would produce a random imbalance. For vehicles that exhibit imbalance (very rare), contact Technical Assistance.
Inspect for the following conditions:
• Metal transfer to the crank post. Replace the crankshaft if metal has been transferred to it or it is damaged.

• Metal transfer or damage to the timing chain sprocket face. Replace the sprocket if either condition is present.

• Verify that the bolt does not bottom out in the crank post.





Install the new washer onto the crankshaft and push into place by hand.
Install the new balancer paying attention to line up the scribe mark.



Use the J 41665 in order to install the balancer.
Assemble the threaded rod, nut, washer and installer. Insert the smaller end of the installer into the front of the balancer.
Use a wrench and hold the hex end of the threaded rod.
Use a second wrench and rotate the installation tool nut clockwise until the balancer is started onto the crankshaft.
Remove the tool and reverse the installation tool. Position the larger end of the installer against the front of the balancer.
Use a wrench and hold the hex end of the threaded rod.
Use a second wrench and rotate the installation tool nut clockwise until the balancer is installed onto the crankshaft.
Remove the balancer installation tool.
Notice: Failure to apply proper torque to the old balancer bolt may result in the balancer not being fully seated. This could lead to failure of this joint in the future.

Install the old balancer bolt and tighten.

Tighten
Tighten the old balancer bolt to 330N•m(240 ft. lb).

Important: The nose of the crankshaft should be recessed 2.4-4.48 mm (0.094-0.176 in) into the balancer bore.






Remove the old bolt and measure the hub to crankshaft distance.
Coat the three to five threads of the new bolt with thread locker (LOCKTITE™ 272) P/N 12345493 before installation.
Notice: Be sure to follow the torque procedure for installing the new crankshaft bolt. Use of impact tools, or not using torque and angle method will result in joint failure.

Install and tighten the new crankshaft bolt.
• Tighten the crankshaft balancer bolt a first pass.

Tighten
Tighten the crankshaft balancer bolt a first pass to 50N•m (37 lb ft).

Put a paint stripe on the bolt running from the 12 o'clock to the 6 o'clock position in order to verify the correct torque requested in the next step.

• Important: When tightening for the second pass, a minimum torque of 320 N•m (236 lb ft) should be observed. If this torque is not achieved, the bolt should be replaced.


Tighten the crankshaft balancer bolt a second pass.

Tighten
Tighten the crankshaft balancer bolt a second pass to 140 degrees using the J 45059.

Important: Recheck the position of the previously painted stripe to assure 140 degree rotation. Achieving the correct torque angle is critical to the success of this repair. Over-torquing or under-torquing the joint will result in an unsatisfactory repair.



Remove the J 42386-A Flywheel Holding Tool.
Install the starter and bolts. Tighten the starter bolts.

Tighten
Tighten the starter bolts to 50 N•m (37 lb ft).

Important: Orient the purple lead wire to the 10 o'clock position when installing.






Connect the starter wiring.
Install the starter motor S terminal washer and purple lead wire (1).
Install the S terminal nut (2) and tighten.

Tighten
Tighten the S terminal nut to 4 N•m (35 lb in).

Important: Orient the gray and rust harness leads to the 6 o'clock and 7 o'clock position.


Install the gray and rust harness leads to the solenoid.
Raise and align the cradle.
Install and tighten the cradle nuts.

Tighten
Tighten the nuts, using hand tools only, to 110 N•m(81 lb ft).

Install and tighten the engine mount nuts.

Tighten
Tighten the nuts to 65 N•m(48 lb ft).

Install the A/C belt.
Install the cooler line bolts.
Install the fan shroud assembly and bolts.

Tighten
Tighten the bolts to 5 N•m(44 lb in).

Position the stabilizer shaft and install insulator clamps and bolts.

Tighten
Tighten the stabilizer shaft insulator clamp bolts to 58N•m (43 lb ft).

Install the tie rod to the steering knuckle.
Install the outer tie rod end stud nut to the outer tie rod end stud and tighten .

Tighten
Tighten the outer tie rod end stud nut to 20 N•m(15 lb ft) to seat the stud.

Turn the nut an additional 160 degrees.
Check for the outer tie rod end stud nut for a minimum final torque of 45 N•m(33 lb ft).
Install the lower ball joint to the steering knuckle.
Tighten the lower control arm ball joint stud nut.

Tighten
Tighten the nut to 20 N•m (15 lb ft) to seat the ball joint stud.

Turn the ball joint stud nut an additional 210 degrees.
Check the ball joint stud nut for a minimum final torque of 55 N•m (41 lb ft).
Install the shock bolts and tighten.

Tighten
Tighten the shock absorber lower mounting nuts to 28 N•m (21 lb ft).

Repeat tie rod, lower ball joint and shock for the other side.
Install the tires and lug nuts.



Important: Tighten the nuts evenly and alternately in order to avoid excessive run out of the tire and wheel assembly.


Using the J 39544-KIT , tighten the wheel nuts in the appropriate sequence shown.

Tighten
Tighten the nuts in sequence to 140 N•m(100 lb ft).

Remove the support jack.
Remove the Leaf Spring Compressor (J 33432-A).
Lower the vehicle.
Remove the engine support fixture.
Remove the engine support links.
Install the upper radiator support and tighten the bolts.

Tighten
Tighten the bolts to 9 N•m (80 lb in).

Install the coolant and EVAP lines to the fan shroud.
Install the engine cover and oil fill cap.
Install the intermediate shaft.
LOCTITE™ the steering intermediate shaft bolts and install.

Tighten
Tighten the lower coupling retaining bolt to 34 N•m (25 lb ft).

Install the generator and tighten the bolts.

Tighten
Tighten the generator bolts to 50 N•m(37 lb ft).

Connect the generator wiring.

Tighten
Tighten the battery feed cable nut to 13 N•m(10 lb ft).

Install the new accessory belt.
Install the air duct and box.
Connect the battery cable to the battery.
Perform a crankshaft variation relearn procedure.
Parts Information
Order a washer from the WPC using the form at the end of this bulletin. Fax the request form to the WPC at 248-371-0192, or E-mail to warrantypartscenterusa@gm.com .

All other parts should be ordered from GMSPO. Use the normal ordering process for all orders.



Warranty Parts Center Parts WPC Part Number
Description
Qty

305
Washer, Crankshaft Balancer
1



GMSPO Parts Part Number
Description
Qty

12557840
Bolt, Crankshaft Harmonic Balancer
1

12583637
Balancer, Crankshaft Harmonic
1

12579229
Belt, Water Pump, Power Steering and Generator
1 as req'd

12579228
Belt, Air Conditioning Compressor
1 as req'd


Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

J0710
Pulley, Crankshaft Balancer - Replace
2.3 hrs

Part Request Form -- Warranty Parts Center To: Warranty Parts Center

WPC E-mail: warrantypartscenterusa@gm.com

WPC Fax #: 248-371-0192

Attn: Jeanette Dunn


Part Being Requested: 305


Dealer BAC (U.S.) / Dealer Code (Canada):



Dealer Name:



Dealer Address:






Dealer Contact Person:




Dealer Phone Number:




Repair Order Number:





Vehicle VIN:






Important: If you do not receive the part within 2 business days after e-mailing or faxing your part request to the Warranty Parts Center, please call WPC Customer Assistance at 248-371-9901/9902.

Hoonose

From what I recall the chance is quite low even in the proper VIN range. It's like a 2% chance. So you probably won't have a problem.

arcticblast

Thanks for the TSB info.

mikeyc6

I see the TSB has been updated. The process appears the same but more details have been added to show what a complex fix this is. I just took the time to read the TSB from start to finish and I have no confidence whatsoever that your average GM tech (even if a "Corvette Tech") could perform these procedures without a foulup somewhere along the way. After reading this, I'm 100% convinced that I'd rather have this happen to me in the worst of places when I least expect it than try to have my local dealer fix this. If it has to be fixed, there's no choice. For now, I'll take my chances! I really think the chances of a screwup in procedures that complex is probably more likely than the crank bolt failing.

Maybe it's just me, but I've seen the incompetence of some of these mechanics that can't even balance a wheel properly, so maybe if this becomes a recall, is commonplace, and they've already done 100 others successfully, then I'll consider it.

Oh, also, they left out a very important step at the very bottom of the TSB! The final step should be "perform an alignment to manufacturer specs".

Mike

StanNH

You will not "probably" have a crank pulley bolt problem. It's still a relatively uncommon failure, although you "may" have a failure because your car doesn't have the later fix. Best current guess is that fewer than 3-5% of the affected cars have actually failed.

juiceman03070

Crap---PURE CRAP....You are a programmer not a C6 tech....I had mine done as elective repair and if I didnt tell you you could never tell it had been done...The tech that did mine has 26 years with the same dealer He met with me before and after and I could not have been more impressed by his professinalism....To a guy like you that has more than likely never even opened up a small block motor to see whats inside , it might seem like "brain surgery" but to a real mechanic it is just another day at work...By the way this guy is assigned to my C6 for all service and checkups....

juiceman03070

Just to add a bit....He said it takes almost as much time to get all of the proper tools out of the tool ben , as it does to complete the job....I actually watched the whole process and sleep alot better at night..

StanNH

I agree with Dwight completely on this. BUT....we're fortunate in that we both have great dealerships with top notch Vette technicians to service our cars. Like Mikey, I was very hesitant to let anyone work on my car to fix something that wasn't broken. The recent rash of high mileage failures has changed my mind on that. My dealer has offered to do the fix as a preventative measure, under warranty. I finally said yes and am just waiting for them to get in one tool needed to do the complete job.

For most of us, the bolt will never fail, fix or no fix. It's just something that's there, always in the back of my mind. I really don't want to waste any more time and energy on this...that's why I finally said yes.

mikeyc6

Like Stan said, you guys are lucky to have mechanics that know what they are doing. I've had a lot of bad luck here in Maryland and from my own experience, the majority of mechanics are simply inept! Also, don't run off at the mouth with assumptions. Some "programmers" are damn good mechanics and could tear a small block down from top to bottom and know what they are doing. I happen to be one of them. No, there is nothing complicated about the procedures, but that assumes you know how to follow them. That's a big assumption with Mr. Badwrench! If I see any failures start happening in the <3000 VIN range, I may actually do it myself provided I can get access to the needed tools. Or... I may just pin it and forget about the washer bandaid.

Again, congrats on having access to capable mechanics, but no thanks... I don't feel like playing Russian Roulette with the inept mechanical "talent" I've seen around here.

Edit: And I hope you are using the term "C6 Tech" loosely. I have to drive an hour to get to a dealer that has a real Corvette team of mechanics. At most dealers, you'll get whatever garden variety Chevy mechanic happened to show up for work that day and it may be the first time he's ever seen a C6 much less worked on one! I wish the world of GM repair was as pristine a picture as you paint it. Unfortunately nearly every time I've had to take any GM vehicle in for service, I've either had to redo the work myself or physically go there and show them how to do it right. I've had to show them how to properly install a flywheel and shim a starter motor, how to use the proper gas cap when you replace one, how to rethread bolt holes on transmission oil pans that they've stripped, how to replace a valve body in an automatic transmission, and I've even had to educate one dealer on how to use their own Tech II! If you had some of the experiences I've had through the years with GM mechanics, you might not paint such a pretty picture of them. Again, I'm happy for you that you don't have to go through such crap.

Mike

crabman

The corvette trained tech at my dealership did not even know how to lift the car. I had to show him. At work I could see he knew how to turn a wrench. Just doesnt much corvette work and mine was the first C6 he had touched.