Safety precautions to avoid damage to the catalytic converter (BMW 3 Series E46)

To avoid damage to the catalytic converter, the following requirements must be met:

Petrol engines

• Use only unleaded gasoline.
• Starting a petrol engine by pushing or towing is permitted only after one attempt and at a distance of no more than 50 m. It is better to use an auxiliary cable for this purpose. Unburned fuel during ignition can lead to overheating of the catalytic converter and its destruction. If the engine is warm, starting it by pushing is not permitted.
• If you have difficulty starting the engine, do not engage the starter for too long. This will cause continuous fuel injection. It is necessary to identify and eliminate the cause of the malfunction.
• Never empty the fuel tank completely.
• If misfiring occurs, do not increase engine speed and correct the problem immediately.
• Use only BMW approved spark plugs.
• Do not perform a spark test with the spark plug connector disconnected.
• Do not perform a cylinder check by cutting off the ignition of any cylinder. When any cylinder is cut off, unburned fuel enters the catalytic converter.

Petrol and diesel engines

• Do not park the vehicle over dry leaves or grass. The exhaust system in the area of the catalytic converter is very hot and radiates heat even after the engine has stopped.
• Do not apply underbody protection products to exhaust system components.
• Do not modify the design of heat shields.
• When filling the engine with oil, pay special attention to never exceeding the level indicated on the indicator as Max. Excess oil due to incomplete combustion enters the catalytic converter and can damage its alloy metal coating or completely destroy the catalytic converter.