My car (2007 Nissan Maxima) has a rattling heat shield. It has been rewelded once and is now rattling again.
Would it be unsafe to remove it?
Is it absolutely needed?
What side effects may I have if I remove it?
Heat shields have two purposes. If it is between the floor and the exhaust system it is designed to prevent the heat from warming the floor and possibly melting the carpet. GM had issues in the late 70s with floor pans rusting from the heat of the catalytic converter. If the heat shield is on the bottom of the exhaust it is to prevent the hot exhaust from setting grass leaves or other debris on fire. Car makers do not typically spend money of parts that are not necessary. You can try to connect several large hose clamps and go around shield and clamp it in place.