GM Issues New Service Bulletin On How to Fix the Z06’s LT6 Engine Ticking Noise

By
Keith Cornett
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5
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GM Issues New Service Bulletin On How to Fix the Z06's LT6 Engine Ticking Noise


About two weeks ago we heard from a Z06 owner whose car was one of those with the excessive ticking noise coming from the LT6 V8 engine. As you may recall, some owners have said their car starts ticking loudly as it reaches operating temperature. GM had issued a preliminary service bulletin that offered a sound clip of the ticking noise, and also stated that no drivability issues were present with the noise.

Now we have new Technical Service Bulletin on the issue which details more about the fix which Chevrolet says is a condition caused by the misalignment of the camshaft caps. That TSB can be downloaded here. As part of the diagnosis, service techs are required to use a picoscope to determine if the ticking noise is coming from the left bank (driver side) or right bank (passenger side).

The TSB gives examples of the ticking sound captured by a picoscope. The top graph is from an engine with the ticking noise while the bottom graph is an engine with no ticking sound:

picoscope examples


If the picoscope confirms the ticking noise is present, then the service tech can move forward with the fix. If the noise is coming from the left bank of the engine, the camshaft cap adjustment procedure can be done with the engine in the car, but if it’s coming from the right bank, the engine will need to be removed to gain access to perform the repair.

The TSB also provides a list of parts that may be needed, as well as the service time needed to make the repairs. For the Left Bank, that time is 6.6 hours for Convertibles and 9.9 hours for Coupes. If it’s the Right Bank, service can take 16.6 hours for the convertible and 17.3 hours of the Coupe.

One of those owners with the ticking noise is a member of the MidEngineCorvetteForum and he had previously stated that his car was going to be one of the first to have service work done to eliminate the noise. Now that that work has been completed, he says the engine is “very quiet now, at least 95% better.” He adds that GM didn’t provide “any paper work with the repair.” As an added bonus, the dealership re-detailed the car for him prior to picking it up.

GM Issues New Service Bulletin On How to Fix the Z06's LT6 Engine Ticking Noise


The TSB notes that due to the LT6’s mechanical valve train design, there will be some mechanical tick noise which is normal. The excessive ticking noise can best be heard while the engine is idling and it’s more noticeable with the hatch open and in Tour mode.

Finally, the TSB shows there are no specific VINs included or excluded, so potentially any LT6 produced in 2023 could have this condition.

Click here to view and download the technical service bulletin.


Source:
MidEngineCorvetteForum.com

Related:
GM May Have a Solution to the LT6’s Ticking Noise
[VIDEO] Chevrolet is Investigating a Ticking Sound from the Z06’s 5.5L LT6
GM Has Issued a Service Bulletin for the LT6 in Regards to Oil Leaking from Front of Engine

 



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5 COMMENTS

  1. Hmmmm. I thought these engines were ran rather extensively prior to delivery. Are Z06 owners hearing this ticking noise after adding miles or day one?
    No one want their car’s engine pulled since it introduces potential issues post repair. It is, what it is I suppose.

  2. The assemblers name is on the engine. I don’t want the ones he builds! So the caps were delivered loose? All that’s done is an 11ftlb retorque?

  5. I own the above car,from what I understand, each cam cap should be torqued with no spring load on the cam,with the lobes straight up,not contacting the rockers. Apparently some builders did not follow this procedure. The re torque of the caps made a huge difference in sound.

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