Reasons to be skeptical: While piston slap *can* occur in a Corvette's LS1 or LS2 engine (depending on the specific Corvette model year within 2005), it usually presents as a distinct, metallic knocking sound, most noticeable when the engine is cold and starting up. The sound typically diminishes as the engine warms up. If the noise persists even when the engine is hot, or if it's a different kind of noise (grinding, whining, ticking, etc.), piston slap is less likely.
Reasons it *could* be piston slap: The LS engines, while generally robust, aren't immune to wear and tear. If the engine has high mileage or has been poorly maintained (lack of oil changes, using incorrect oil viscosity), piston slap could develop.
What to do:
* Get a second opinion: Absolutely crucial. Take your Corvette to a different reputable mechanic, ideally one specializing in Corvettes or GM vehicles. Describe the noise in detail – when it occurs (cold start, hot engine, under load, etc.), what it sounds like (knocking, ticking, grinding, etc.), and its intensity.
* Listen to the sound yourself (if possible): If you can record the sound, share it with the mechanics for a better diagnosis.
* Check the maintenance records: A full service history will provide valuable clues about the engine's condition and potential wear.
* Consider the mileage: Higher mileage increases the likelihood of piston slap or other wear-related issues.
Other potential causes of engine noise:
* Rod knock: A much more serious problem than piston slap, indicating severe engine damage. This sound is usually a more consistent, louder knock.
* Connecting rod bearing wear: Similar to rod knock, but potentially a less severe initial issue.
* Valvetrain issues: Worn lifters, rocker arms, or pushrods can create various ticking or clicking noises.
* Timing chain/belt issues: Can produce a rattling or whining sound.
* Exhaust leaks: Can create a variety of sounds depending on the location of the leak.
In short, while piston slap is a possibility, don't automatically accept the dealer's diagnosis. Seek further professional opinions and thorough investigation to determine the true cause of the noise before undertaking any expensive repairs. A misdiagnosis could lead to unnecessary and costly repairs.
