Handling of catalytic converters in vehicles (BMW 5 Series E39)

To avoid damage to the oxygen sensor and catalytic converter, the following instructions must be strictly observed:

Petrol engines

Be sure to refuel with unleaded gasoline only.

It is not allowed to start the engine warmed up to the operating temperature by pushing or towing. If necessary, start the engine from the battery of another vehicle. Once in the catalytic converter, unburned fuel can cause it to overheat and break down in a flash.

If difficulties with starting arise, do not keep the starter on for a long time. Fuel is constantly injected during starting. Determine the cause of the malfunction and eliminate it.

Never empty the tank completely when driving.

If ignition problems occur, avoid running the engine at high crankshaft speeds and immediately eliminate the cause of the malfunction.

Use only standard spark plugs.

Do not perform any spark checks with the spark plug cap removed.

No comparative evaluation of cylinder performance can be made by switching off the ignition of one cylinder. When switching off the ignition of an individual cylinder - also via an engine test stand - unburned fuel gets into 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 coating to the exhaust system.

The heat shields of the exhaust system must not be modified.

When filling and refilling the oil level, pay special attention to the fact that the maximum permissible level is never exceeded. Otherwise, as a result of incomplete combustion, excess oil gets into the catalytic converter and can damage the precious metal or completely destroy the converter.