Exhaust issues

[swazi]

My avensis a 2009 model with 1.8vvti engine. I had the rear silencer replaced and suddenly had problems with the cat heat shield. After 3 exhaust removals and ex large washers used the excessive noise has gone.

The exhaust folk told me the heat shield was not required. My question is, if the shield is not required then why is it there, and, where would one obtain a replacement shield