Introduction

Many 2002 Nissan Altimas may face an excessive oil consumption issue. This can result from a faulty catalytic converter that allows debris to contaminate the oil system. As a resolution for this guide, we will go through the process of replacing the catalytic converter. Please note that this guide requires a certain level of expertise.

Tools Required

• Ratchet set
• Jacks or lifts
• Screwdrivers (Phillips and flathead)
• Torque wrench
• Replacement catalytic converter

Diagnostic Steps

• Unusual oil consumption: Excessive oil use is a direct indication of this issue.
• Performance decrease: The damaged catalytic converter restricts exhaust flow leading to reduced performance.

Repair Guide

1. Raise the vehicle using a jack or lift for easier work access.
2. Locate the catalytic converter. It's present on the underside between the engine and the muffler.
3. Use a ratchet set to remove the bolts connecting the converter to the exhaust system.
4. After removing the bolts and detach the O2 sensor, you can remove the old catalytic converter.
5. Perform a quick inspection of the area around to ensure there are no leftover debris that might hamper the new converter.
6. Now, mount the replacement converter in place and secure it with new bolts. Ensure it's properly aligned before tightening the bolts with a torque wrench.
7. Re-attach the O2 sensor and lower the vehicle back to the ground.

Potential Pitfalls and Repair Tips

A common issue often faced while replacing a converter is rusted or stubborn bolts. Might require lubricant or a torch to heat them up for easier removal. Always perform a post-repair test drive to ensure that the issue has been resolved successfully. Regular oil checks are advised to ensure the problem doesn't persist.