Hello, I have a 2011 Honda Accord V6, 4-door sedan, automatic transmission, around 134k miles. In recent weeks, as weather got colder, my car seems to have developed a weird noise when startup in cold mornings. It sounds like metal grinding/hitting each other. Sometimes it lasts a few seconds, sometimes over 10 s. This only happens during the first time I start my car each day. If I start my car for the 2nd time at noon, I typically do not hear it.
Here is an example of the noise. In the video, the noise appears at round 10s, lasts for about 5 s, and then disappears again.
https://youtube.com/shorts/ilFoNEMAza4
Could someone let me know what is going on here? Thank you very much.
I wonder how serious it is.
Depends if it's about to fall off or not. First you need to find it. It sounds like it might be right under your hood, so look at your exhaust manifold and poke around with a screwdriver.
Very easy to fix:
https://www.youtube.com/watch?v=weDs7HvepFA
that sounds exactly like a loose vibrating heat shield
Thank you for your reply. I wonder how serious it is. Do I need to take actions immediately? Just wonder roughly how much would it cost?