Mercedes GL-Class Catalytic Converter

The catalytic converter in your Mercedes GL-Class is a crucial part of the exhaust system that transforms harmful engine emissions into less polluting substances. It operates by using a chemical process called catalysis to reduce hydrocarbons, carbon monoxide, and nitrogen oxides in exhaust gases. Precious metals like rhodium, platinum, and palladium coated on honeycomb-shaped ceramic plates facilitate these chemical reactions.

The Mercedes GL-Class catalytic converter relies on two key reactions:

• Reduction Catalysis: Using rhodium or platinum to reduce nitrogen oxides (NOx).
• Oxidation Catalysis: Using platinum and palladium to oxidize unburned hydrocarbons and carbon monoxide.

Exhaust gases pass through ceramic honeycomb structures coated with these precious metals. For optimal operation, the catalytic converter must reach around 420°C, which is why it is generally mounted close to the engine.

During the first few minutes after a cold start, the catalytic converter does not effectively reduce emissions because it needs to heat up to its optimal operating temperature (~420°C). While warming up, the exhaust gases emitted by the vehicle are more polluting. This is particularly noticeable in cold weather.

The Mercedes GL-Class diesel models feature an advanced BlueTEC emission control system. This system injects AdBlue (a urea solution) that generates ammonia, which is then converted by an additional catalytic converter to nitrogen and water in about 80% of the injected amount. This process significantly reduces nitrogen oxide emissions by approximately 80%.

• Reduced engine performance, such as power loss, slower acceleration, and increased fuel consumption.
• Resonance noises from inside the catalytic converter due to damaged or detached ceramic plates.
• Warning light activation caused by oxygen or air-fuel ratio sensors detecting system faults.

As of January 2026, used catalytic converters for Mercedes GL-Class can range from approximately 221 USD to 787 USD, reflecting the value of the precious metals contained within. Prices for new parts will vary, and all parts must be compliant with applicable emissions and quality standards.

To ensure optimal catalytic converter function:

• Use high-quality fuel.
• Maintain a properly working exhaust system.
• Keep a stable air-fuel ratio, managed by oxygen sensors (lambda sensors) located near the catalytic converter.

If the catalytic converter becomes clogged or dirty due to insufficient temperature or poor maintenance, replacement may be necessary.

Krosfou offers brand-new, high-performance Mercedes GL-Class catalytic converters with a 3-year warranty limited to 100,000 kilometers. The warranty covers defects if installation instructions are properly followed and the part is used correctly. A free return policy applies within 30 days for unused and original parts returned in their original packaging in France or Europe.

Fast delivery options are available:

• Standard delivery in Europe: 1 to 6 working days, free for orders over €157.50 excluding VAT.
• Express delivery in Europe: 24 to 48 hours, price depends on carrier.
• International standard delivery: 8 to 15 working days, starting from €38.20 excluding VAT.
• International express delivery: 2 to 4 working days, price varies with carrier.

All products comply with strict European manufacturing and quality standards, ensuring reliability and efficiency for your vehicle's emission system.