* Bearing Failure: This is the most common cause of knocking in a supercharger. The bearings, which support the rotors, can wear out due to age, lack of lubrication, or excessive heat. A failing bearing will create a distinct knocking or rumbling sound, especially under load.
* Looseness/Worn Components: Internal components like the rotors themselves could be worn or loose, leading to a knocking sound as they impact each other or their housings.
* Interference: Something might be interfering with the supercharger's rotors – a foreign object, a damaged impeller, or even a piece of debris.
* Pulley Issues: A worn or damaged supercharger pulley can also cause a knocking noise.
* Drive Belt Problems: While less likely to be a *direct* cause of knocking *from* the supercharger, a slipping or excessively worn drive belt could lead to irregular rotation and stress on the bearings, potentially contributing to the sound. This would likely present with other symptoms like squealing too.
Ignoring the knock is dangerous. Continued operation with a failing supercharger can lead to catastrophic failure, potentially damaging the engine itself. The supercharger could seize up, causing significant internal damage.
What you should do:
1. Do not drive the car: Continued driving risks further damage.
2. Have it professionally diagnosed: Take your Grand Prix to a qualified mechanic, ideally one experienced with supercharged vehicles. They can pinpoint the exact cause and recommend the necessary repairs. Trying to diagnose and fix this yourself is risky and could worsen the problem.
3. Prepare for a significant repair cost: Supercharger repairs can be expensive, depending on the extent of the damage. Replacing the entire supercharger is a possibility.
In short, a knocking supercharger is a serious problem requiring immediate professional attention. Driving with this issue could lead to costly engine damage.
