We’ve recently been hearing reports of owners picking up their brand new 2020 Corvettes from the dealer and getting 25 miles away when suddenly, the car goes into limp home mode and warning lights come on.
Upon further investigation, the root cause is a valve spring failure.
On September 22, GM issued TSB #PIP5752A: Service Engine Light misfire engine noise With DTC P0300 P0106 P0506.
The service bulletin includes 2020 Corvettes, Camaros, Silverados and GMC Sierras as well as 2021 Suburbans and Tahoes.
As per the bulletin:
During inspection if you determine that the engine has a broken valve spring it will be necessary to perform a cylinder leakage test on the affected cylinder.
If no cylinder leakage is observed it will be necessary to replace all valve springs on both banks if the vehicle is built between June 1, 2020 to September 15, 2020. Note: This only applies to the 6.2L engines RPOs L87, LT1, LT4 and LT2. For all other engine RPOs L82, L84 and L8T just replace the affected valve spring.
GM is requesting that Chevy dealers return all of the valve springs for further inspection and analysis.
Given that this TSB affects multiple platforms, it’s safe to assume that it isn’t an assembly issue, but rather a materials composition issue with the valve springs from the supplier.