Your Ford E350's catalytic converter makes for a relatively environment-friendly van that meets your state's emissions standards. It has a tough job and, like any other part of a vehicle's exhaust system, it is exposed to a lot of heat, pressure, and corrosive elements. When your van's converter breaks down, you will experience different problems ranging from elevated emissions to poor engine performance. Unfortunately, there is really no way to repair or maintain this component. Other than not using leaded gasoline (which will contaminate and the converter and cause failure), the best you can do is replace it when it's time is up. Your "Check Engine" light is one indicator, but it isn't specific enough. Look out for the following signs:
The rattling sound is most likely a broken honeycomb disk inside your converter. This means the component has suffered an internal breakdown and needs to be replaced. However, you won't expect this symptom with pellet-type converters.
This points to a clog in the catalytic converter. Unfortunately, you cannot simply unclog the component. You will need to replace it with a new one.
When all your engine's horsepower seems to take forever in turning your van's trot into a gallop, and you find that it makes mountains out of molehills, then it points once again to a severely clogged catalytic converter. Because of the restricted exhaust flow, high back pressure on the engine is created, affecting performance and causing it to overheat. Other performance issues caused by a malfunctioning converter include rough idling, stalling, and a drop in fuel economy.
Because the catalytic converter is responsible for cleaning your engine's exhaust, you can expect higher emissions when the converter fails. Dangerous chemicals like carbon monoxide and hydrocarbons are released into the atmosphere.
Perhaps the clearest sign that you need a new catalytic converter is when you look under your vehicle and find that your old converter is simply gone. Such an issue is not caused by any engine or component failure. Rather, it is the result of theft. Your converter contains expensive catalysts like platinum, palladium and iridium, making it a target for thieves. Make sure you park your vehicle in secure areas. Other preventive measures include welding the converter in place, using a "cage clamp," or installing an alarm device.