What You'll Learn
Aussie Conditions
Look, if you're living in Australia, your car's belly is constantly under attack. Between the salt air on our coasts and that bloody red dust that gets into every crevice out west, the metal underneath doesn't stand a chance without some help. This guide covers how to deep clean and protect your underbody so it doesn't turn into a block of Swiss cheese in five years. It's not the most glamorous job, but it's the one that'll save you thousands in the long run.
Why Bother with the Underbody?
The Gear You'll Need
What You'll Need
While you're here...
Preparation is Everything
The Initial Blast
Give the whole underside a heavy rinse with fresh water. If you've been in red dust, this might take a while. I once spent three hours just washing a Hilux that had come back from the Kimberley, the red mud was like concrete.
Lift it Up
Jack the car up and put it on stands. If you can get it on a hoist, even better. The more room you have to move, the better job you'll do.
Degrease and Scrub
Spray your degreaser liberally across the oily areas and heavy mud spots. Let it dwell for 5-10 minutes (don't let it dry!) then give it a scrub. This gets rid of the road grime so the protectant actually sticks to the metal, not the dirt.
The Step-by-Step Protection Process
Dry it Out Properly
This is where most people mess up. You cannot spray sealant over water. Use a leaf blower or leave it in the sun for a few hours. Any moisture trapped under the coating will cause rust. (I learned this the hard way on a black Commodore I worked on years ago, rust bubbles appeared within months).
Inspect for Existing Rust
Check the welds and corners. If you see surface rust, hit it with a wire brush and some rust converter before moving on. Don't just paint over it.
Mask Off Sensitive Bits
You don't want lanolin or wax on your brake rotors, exhaust system, or rubber bushes. Chuck some old newspaper or plastic over the brakes. Trust me, trying to stop with lanolin-coated pads is a heart-starter you don't need.
Apply Cavity Wax
Using the long straw attachment, feed the wax into the holes in the chassis rails. Give it a good blast as you pull the straw out. This is where the real protection happens.
Spray the Main Rails
Start from the front and work your way back. Get a nice, even coat of your lanolin spray on the chassis rails and cross members.
Hit the Wheel Arches
These take a beating from stones and sand. Give them a heavy coat. If you've got plastic liners, try to spray behind them if you can.
Don't Forget the Diff and Axles
Spray the exterior of the diff housing and axles. Avoid the breather valves though, you don't want to clog those up.
Check the Fuel Tank and Lines
Give the straps and the tank itself a light coating. These often get missed and are prime spots for corrosion.
Wipe Down Overspray
Check the lower panels of your paintwork. If any protectant drifted up onto the shiny bits, wipe it off now with some prep-sol or a bit of degreaser on a rag.
Final Inspection
Get a torch and look for any dry spots. It should look slightly 'wet' or 'waxy' everywhere when you're done.
Watch Out
The Lanolin Smell
Watch Out
Maintaining the Protection
Common Questions
Can I use old engine oil instead?
Will this void my warranty?
How often should I do this?
What's the best product for red dust?
Trusted by 50,000+ Aussie car owners
Professional advice for Australian conditions
Products We Recommend
Keep Learning
Ready to level up your car care?
You've got the knowledge—now put it into action. Explore more guides or check out our recommended products.
Get Weekly Car Care Tips
Join 12,000+ Aussie car enthusiasts
Keep Reading
Beach Driving Aftercare: Getting the Salt and Sand Out
Driving on the beach is a classic Aussie weekend, but the salt will eat your chassis alive if you aren't careful. Here is exactly what you need to do to stop the rot before it starts.
Keeping the Rot Away: Your Underbody Rust Prevention Checklist
Living in Australia means your chassis is constantly under attack from salt spray and red dust. Here is exactly what you need to stop your pride and joy from turning into a pile of iron lace.
Keeping the Rot Away: The Real Way to Stop Underbody Rust
Underbody rust is the silent killer of Australian cars, especially if you're hitting the beach or living near the coast. I'll show you how to properly clean, treat, and protect your chassis so it doesn't crumble into a pile of iron oxide.
Keeping the Rust Off: How to Protect Your Underbody from Salt and Red Dust
Living in Australia means your car's undercarriage is constantly under attack from coastal salt or abrasive outback dust. This guide shows you how to clean, seal, and protect your chassis before the winter rains hit.