2000 Subaru Impreza Owner's Manual - Page 178

NOTE Due to the expansion and contraction of the metals used in the manufacture of the exhaust system, you may hear a crackling sound coming from the exhaust system for a short time after the engine has been shut off. This sound is normal. Catalytic converter D Avoid fire hazards. Do not drive or park the vehicle anywhere near flammable materials (e.g. grass, paper, rags or leaves), because the catalytic converter operates at very high temperatures. D Keep everyone and flammable materials away from the exhaust pipe while the engine is running. The exhaust gas is very hot. WARNING HB3003BA The catalytic converter is installed in the exhaust system. It serves as a catalyst to reduce HC, CO and NOx in exhaust gases, thus providing cleaner exhaust. To avoid damage to the catalytic converter: D Use only unleaded fuel. Even a small amount of leaded fuel will damage the catalytic converter. D Never start the engine by pushing or pulling the vehicle. 7-8