Heat shield maybe?? on 2008 Nissan Altima

When my car is stopped at a light or when I first shut it off it makes these clunking noises, almost like expanding pipes, but it did not do that for the first 20,000 miles. They replaced the heat shield and it still makes the noise. Any ideas?

1 answer
The heat shields were a problem there were service bulletins from Nissan about that. There may be other shields that are corroded, or it just may be normal metal expansion and contraction.