Nissan Altima Water Leak Under Car: Troubleshooting Guide

Finding a puddle underneath your parked Nissan Altima can be both worrying and frustrating. 

Water leaks in any vehicle need to be addressed quickly before major damage occurs.

Fortunately, with some diligent troubleshooting and repair work, you can track down the source of most Altima water leaks and prevent further issues. 

Here is a Guide to Finding and Fixing the Common Causes of Water Intrusion in your Altima

Inspect the Door Seals

• One of the most common places to find water intrusion in your Altima is through the door seals. 

• Make sure the rubber seals around the doors are in good condition and haven’t become dry and cracked. 

• This is because damaged or missing door seals can allow rainwater to seep into the cabin. 

• Carefully examine each door seal and replace any worn sections.

Check Windshield Moldings

• Leaking windshield moldings are another common issue. 

• Make sure the molding strips that surround the windshield are adequately sealed and haven’t become loose. 

• Gaps around the windshield can let water drain into the surrounding channels and footwells. 

• Re-adhere any loose moldings with fresh automotive sealant. Also, examine the sunroof and rear window for tight sealing.

Look For Plugged AC Drain Hoses

• Your Altima’s air conditioning system should have a drain hose under the car to channel condensation away. 

• If this AC drain gets clogged with debris, water can back up and leak into the cabin. 

• Locate the drain hose and use a small wire to clear any blockages and get water flowing freely again.

Scan for Leaking Sunroof Drains

• If your Altima has a sunroof, check the sunroof drain tubes that route water away from the roof. 

• They can become detached or cracked over time by resulting in sunroof water overflowing into the car. 

• Inspect each drain tube carefully and make any necessary repairs. 

• A blast of compressed air can also dislodge any clogs.

Address Rust Around Seams

• Rust formation in hidden body seams or spot welds can lead to leaks around the years down the road. 

• This often shows up around wheel wells, the trunk, and lower door jambs. 

• Sand any problem areas down to bare metal and treat with rust converter primer to stop further spreading. 

• Then, reseal everything to keep the elements out.

Examine the Windshield Cowl and Air Intake

• At the base of the windshield, there is a plastic cowl panel that can warp and crack over time by allowing water into the ventilation system. 

• Inspect this cowl cover and the nearby air intake for any gaps or damage. 

• Reset or replace the cowl cover if needed and reseal the air intake assembly.

Check the Battery Tray

• The battery tray in the engine bay commonly corrodes and develops holes due to chemical leakage. 

• Inspect the tray for any perforations and seal them up with epoxy to prevent water from getting into the fuse boxes below. 

• A new factory replacement tray can be installed if the damage is too severe.

By methodically checking all potential water intrusion points, you can find where leaks are entering into your Altima. Pay special attention to worn seals and drainage systems. With some diligent detective work and preventative maintenance, you can keep unpleasant water leaks from dampening your driving experience.

Frequently Asked Questions About Nissan Altima Water Leak Under Car

Q: Do I need to replace wet carpeting right away?

A: Not necessarily. First, ensure the source of the leak is fixed, then thoroughly dry out the carpets with fans and dehumidifiers to prevent mold growth.

Q: How can I prevent future water leaks in my older Altima?

A: Keep seals conditioned and flexible, address any minor rust spots, and repair collision damage properly. Regular undercarriage washes also helps to prevent rust and clogs.