How to Clean & Protect Your 4Runner Undercarriage After Winter (DIY Guide)

If you daily your 4Runner in winter states—Utah, Colorado, Idaho, Montana, Wyoming—you already know the enemy: salt, magnesium chloride, and road brine. They stick to the undercarriage, eat into unprotected metal, and quietly start corrosion long before you notice anything on the surface.

The good news? You can stop rust before it starts with one solid post-winter cleanup. This guide walks you through exactly how to wash, inspect, and protect the underside of your 4Runner using products you can grab right now from 4RunnerLifestyle.com.

Why Undercarriage Maintenance Matters

Your 4Runner’s frame and suspension take the biggest beating each winter. Even light brine exposure can build up behind:

• Skid plates

• Control arms

• Rear links

• Exhaust components

• Wheel wells

A proper cleanout prevents rust, protects resale value, and keeps suspension components lasting longer.

Step 1 — Wash the Undercarriage Thoroughly

Most automatic washes don’t hit everything—especially if your 4Runner has:

• Aftermarket armor

• Lift kits

• Bigger tires

• Long-travel setups

You’ll want a pressure-washer wand to reach the frame rails and crossmembers.

Step 2 — Check Skid Plates & Armor for Hidden Salt

If you run skids, salt will accumulate behind them.

Consider pulling the front skid off and giving everything a rinse. If your OEM skid is banged up (or you want better winter protection), upgrading now isn’t a bad idea.

Available Upgrade Options:

Rage Fabrication Front Skid Plate (5th Gen)

🔗 https://www.4runnerlifestyle.com/products/rage-fabrication-front-skid-plate-4runner-2010-2023

A stronger steel option with better coverage than stock—plus it resists rock rash and winter corrosion far better than the thin OEM skid.

Step 3 — Apply Undercarriage Protection

Once dry, you can apply a protective coating to help prevent corrosion.

While 4RunnerLifestyle.com doesn’t sell fluids or coatings, you can protect exposed parts using accessories that block buildup.

Popular Add-On:

4Runner Rear Mudflaps (Multiple Models)

🔗 https://www.4runnerlifestyle.com/products/4runner-rear-mud-flaps

Mudflaps drastically reduce road spray hitting the frame and rocker panels—one of the easiest ways to prevent rust formation long-term.

Step 4 — Add Wheel-Well Lighting for Easier Inspections

Being able to see your wheel wells clearly helps with spotting:

• Rust

• Debris pockets

• Leaking shocks

• Damaged brake lines

Clean Lighting Option:

Diode Dynamics  Rock Lights (Universal)

🔗 https://www.4runnerlifestyle.com/products/rock-light-kit

These make it easy to light up the underside for maintenance and trail use.

Step 5 — Keep It Clean Through Spring

Once the big winter wash is done, hit the underside again after:

• Off-road trips

• Driving in heavy rain

• Post-snow transitions

• Dusty trail days

Staying consistent prevents corrosion creep.

Prep Your 4Runner for a Rust-Free 2025

A little maintenance now saves your 4Runner’s frame for the long haul. Grab the accessories that help keep your undercarriage clean and protected.

👉 Shop 4Runner cleaning & protection gear:

https://www.4runnerlifestyle.com/collections/exterior-accessories