Catalytic Converter for Nissan Altima (2013-2018) 2.5L Front

Direct-Fit Front Exhaust Manifold Catalytic Converter for 2013-2018 Nissan Altima (L33)

What it Does: The front catalytic converter manifold replaces degraded factory emissions equipment on the 2013-2018 Altima to eliminate P0420 fault codes, normalize exhaust scavenging, and restore factory tailpipe emissions compliance.

The Stock Nissan Altima Ceramic Washcoat Breakdown

The factory integrated manifold converter on the L33 generation Altima faces chronic thermal cycling stress. Positioned directly against the cylinder head exhaust ports, the factory manifold suffers sustained thermal loading that degrades the internal washcoat and fractures brittle honeycomb walls. Over time, physical substrate erosion triggers downstream O2 sensor divergence, illuminating check engine warnings (P0420) while elevated exhaust backpressure chokes cylinder evacuation on the QR25DE platform.

The Engineering Solution

Constructed from high-grade stainless steel with precision-cut laser flanges, this direct-fit front manifold converter eliminates exhaust leaks and resists high-heat oxidation. Inside, a durable ceramic substrate loaded with precious metal washcoat optimizes catalytic conversion efficiency without choking exhaust flow. Featuring factory-located oxygen sensor bungs and heavy-gauge mounting brackets, this unit installs directly onto the cylinder head without cutting or welding, fully interfacing with OEM hardware references 16694, 641427, 40989, and 674-149.

Technical Specifications

Compatibility

• 2013 Nissan Altima Sedan 2.5L I4 (Base, S, SV, SL)
• 2014 Nissan Altima Sedan 2.5L I4 (Base, S, SV, SL)
• 2015 Nissan Altima Sedan 2.5L I4 (Base, S, SV, SL)
• 2016 Nissan Altima Sedan 2.5L I4 (Base, S, SR, SV, SL)
• 2017 Nissan Altima Sedan 2.5L I4 (Base, S, SR, SV, SL)
• 2018 Nissan Altima Sedan 2.5L I4 (S, SR, SV, SL)

Frequently Asked Questions

Does this fit the L33 Altima?

Yes, this is a direct fit for the 2013-2018 Nissan Altima equipped with the QR25DE engine.

Will this direct-fit converter clear a P0420 diagnostic code?

Yes, renewing degraded catalyst substrate with this assembly restores required conversion efficiency and clears catalytic threshold diagnostic trouble codes.

The Nissan Operational Caliber

Engineered for high-mileage reliability, this manifold maintains optimal backpressure balance and factory O2 sensor feedback to ensure clean tailpipe emissions and smooth throttle delivery across everyday driving conditions.