Warranty Information

• Petrol Catalysts with Ceramic Monoliths are guaranteed for 2 years.
• Steel Monoliths are guaranteed for 3 years.
• All Diesel Catalysts are made with steel monoliths and are guaranteed for 2 years.

Road impact damage

Damage is caused to the catalyst when it hits or is struck by hard objects. This can cause the monolith to fracture and the pieces to rattle around inside the unit. Possible causes include impact from speed humps or off road driving. Evidence of impact damage can usually be seen by the naked eye on the housing of the unit.

Plugged or contaminated monolith

If a monolith becomes coated and blocked with soot, it will be prevented from converting the noxious gases into less harmful ones. Some causes include; a car running rich (too much fuel), incorrect fuel or fuel additives or oil or antifreeze entering the exhaust system. Contamination can also occur through excess amounts of hydrocarbons entering the exhaust. The vehicle should run no higher than 55ppm HC (parts per million of Hydrocarbon) before fitting the replacement catalyst.

Melted or broken monolith

Apart from impact damage, a monolith can be broken as a result of a sudden drop in temperature. This is usually caused when a car is driven through deep water such as a ford. The steel outer casing contracts faster than the ceramic monolith as it cools and crushes it. The monolith can also melt when unburned fuel is injected into the exhaust system. Towing, bump starting or engine misfire are common casues of this. More information on the causes of melting monoliths are summarised below:

Faulty spark plugs and leads or a badly timed distributor

Engine misfiring and/or a badly timed distributor allows unburnt fuel to enter the exhaust system and finally the substrate. Extremly high operating temperatures ignites the fuel causing the substrate to melt and fail.

Faulty oxygen/lambda sensor

The oxygen (lambda) sensor collects information about the oxygen content of the exhaust gases. This data is sent back to the ECU which regulates the air/fuel mixture. A faulty oxygen sensor will lead to an incorrect air/fuel mixture. A too rich a mixture allows elevated levels of fuel through the substrate, causing superheating and melt down. Please change the oxygen sensor when replacing a catalyst.

Faulty fuel injection systems

If a fuel injector is leaking fuel internally or allowing unregulated fuel into the engine, excess fuel will enter the exhaust system and eventually the catalyst causing it to ignite and melt down. On changing a catalyst, please ensure that the fuel injectors are operating normally.

Faulty map sensors

If the map sensors that inform the ECU of the load on the engine and the amount of air entering it are faulty, a rich condition may prevail leading to excess quantities of fuel in the catalyst. Fuel ignition and melt down may be the result.

Faulty carburettor systems

A worn or faulty carburettor can cause a catalyst to overheat and fail. Improper float or air/fuel mix adjustments and worn metering rods can cause damage to the catalyst. The choke system should be operating correctly to ensure correct levels of fuel entering the system.

Faulty canister purge control valve

The canister purge control valve uses a vacuum to vent fuel vapour from the carburettor bowl to the charcoal canister. A vacuum breach allows the charcoal canister to flood and causes the air/fuel mixture to be too rich. Excess fuel will pass through the catalyst which is subsequently burned, melting the catalyst substrate.

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