For a diagnosis, r/MechanicAdvice is the focused choice. r/Cartalk is broader and also allows part and car identification.
Where to ask
Best for: Diagnosing and repairing a specific fault.
Why it fits: Its public description: “This is more than a car repair forum!”
Members in our directory: 2.2M
Rules to know before posting:
- Year, make, model and engine are required on every post.
- One vehicle or problem per thread; post once.
- No tire, audio, insurance, buying or “suing a shop” posts.
- No bodywork, rust or detailing questions.
Read r/MechanicAdvice’s current rules on Reddit
Best for: General talk about your car, plus “what part is this?”
Why it fits: Its public description: “The place to talk about your car”
Rules to know before posting:
- Posts should be about your own car or experience.
- No questions about quotes, estimates or what something costs.
- No “what car should I buy” posts.
- “What car is this” and “what part is this” posts are allowed.
Read r/Cartalk’s current rules on Reddit
Before you post
- Give year, make, model, engine and mileage in the title.
- Record the noise on video, and note when it happens (cold start, braking, turning).
- Include any dashboard warning or error code exactly.
Rule summaries are paraphrased from each community’s published rules (public archive copy retrieved 7 November 2026; original snapshot date unavailable). Current rules may differ — check the community’s rules before posting. A good fit does not guarantee a reply.