1. Identify the Source:
* Isolate the noise: Drive slowly over bumps, listening carefully to pinpoint the general area of the dashboard making the noise. Is it the top, bottom, center, left, or right?
* Reproduce the noise: Try gently pressing and pulling different parts of the dashboard while stationary to see if you can recreate the sound. This helps narrow down the specific component.
* Visual inspection: Look for loose screws, gaps, or broken clips around the suspected area. A flashlight can be helpful.
2. Potential Solutions (from least to most invasive):
* Tighten loose screws: This is the easiest fix. Check all visible screws around the dashboard, especially those holding trim pieces and the instrument cluster.
* Apply lubricant: For plastic-on-plastic rubbing:
* Silicone-based lubricant: Apply a small amount of silicone spray (like WD-40 Specialist Silicone Lubricant – *avoid WD-40 itself as it's a solvent*) to suspected rubbing points. Be careful not to spray directly onto electronics.
* Felt pads or foam tape: These can be strategically placed between parts that are rubbing together to dampen vibrations. Automotive-grade foam tape is preferred.
* Re-secure loose trim pieces: If you've identified loose trim, gently pry it loose (carefully!) and re-attach it. You may need to replace broken clips. Auto parts stores sell replacement clips.
* Address loose components behind the dashboard: This is more difficult and may require partial dashboard disassembly. You'll need to carefully remove the trim pieces to access the components.
* Replace worn parts: If you've identified a broken clip, a worn bushing, or other damaged part, it will likely need to be replaced. Finding replacement parts for a car this age might be challenging, requiring trips to junkyards or online parts sources.
* Professional help: If you're uncomfortable with disassembly, take your DeVille to a mechanic specializing in older vehicles or a reputable auto upholstery shop. They'll have the expertise and tools to properly diagnose and fix the problem.
Important Considerations:
* Safety first: Disconnect the negative battery terminal before undertaking any dashboard disassembly.
* Take pictures: Before disassembling anything, take pictures to help you remember how things go back together.
* Patience is key: This is often a tedious process of trial and error. Start with the simplest solutions and work your way up.
Remember, creaking and rattling noises in older cars are common. While a complete fix might require considerable effort, addressing the most obvious causes can often significantly reduce the noise level.
