RMALINDAK

Can you recommend a good place to get this problem diagnosed and fixed. In my Honda Fit GP1, I get a an annoying vibration/rattle sound (like a vibrating mettle sheet) from dash board (in the area of the car stereo) when the car hit pot holes or in a bad road. I can also recreate the sound by thumping on the dash board or when closing the glove compartment. This happen only when its hot outside. There is no issues at night or early morning, or in rainy or cold days. It happen only when the sun is up and hot. I usually get all work done at agent (Stafford). But I have a feeling that due to nature of the issue, this is more of a job for a mechanic with lot of patient, willing to spend some time going through it to figure it out unless they have dealt with similar issue before. Also if the garage insist on bringing in the car early morning as some do, I wont be able to demonstrate the problem as this is heat/time dependent. Can someone recommend a good place around Colombo for diagnosing and fixing thins kind of thing. Or do you think this is a job for the agent.