4wd Underbody Rust Protection vs Electronic

So, you’re looking for underbody rust protection for your 4WD.

If you’re looking for rust protection, you’re pretty much wanting one thing – No rust in your vehicle.

But you may not be aware of your options, pricing and what you will get.

Basically, you’ll have 2 options for rust proofing your vehicle:

1. Underbody rust proofing Sprays – which stop rusting from taking place in the first place.

2. Electronic Systems – which stop or slow the reaction by replacing the electrons in the vehicle using a negative charge.

To make sure you get the best rust protection for your vehicle, we’ve broken down these options side-by-side to give you everything you need to make a confident buying decision.

4wd Underbody Sprays

How Do underbody 4×4 sprays work?

Sprays attempt to stop corrosion from forming by coating the vehicle or structure and preventing the iron & oxygen coming into contact.

By spraying the underside of your vehicle, you create a physical barrier of protection for your vehicle.


1. Stops rust from forming
2. Prevent structural and surface rust
3. You can check them anytime
4. Professionally applied


1. Don’t cover the entire vehicle
2. Only work on the areas applied
3. May need re-application or touch ups
4. Require check-ups every 6-12 months
5. Complicate Machanic Work (Due to the vehicle being coated)
6. Won't stop existing rust


Main Spray$500-800
Touch Ups$30-100
Total Cost Over 10 Years$500-1100
Cost Per Year (Averaged Over 10 Years)$50-110

Overall Verdict On Sprays

4WD Underbody Rust Protection

Whilst on-going maintenance fees and time commitments may discourage you from choosing an underbody spray, it doesn’t mean that they’re a bad option.

If maintained, a quality spray can see you through any harsh environment that would otherwise nurture rust on your vehicle. 

The initial set-up cost is affordable in comparison to many other solutions on the market, which is great if you haven’t yet got the finances to put towards a better level of protection.

Ratings Explained:

Level Of Protection: Sprays protect against both structural and surface rust, however, do not cover the entire vehicle and often leave many areas that can’t be reached without protection. 

Maintenance Time: Sprays require on-going in-house checkups from your installer 

Install Time:  Install done entirely by the installer, but will require a few hours

Total Cost: This will depend on the type of spray you get. 

Maintenance Cost: Depending on the amount of touch up work or reapplication required

Install Cost: This is included in the cost of the system 

Overall Rating: Taken from an average of the other variable

Electronic Rust Protection

How does electronic rust protection work?

Electronic systems aim to replace lost electrons in steel using a negative charge, ultimately reducing the rate of corrosion.

By fitting an ERPS, you stop rust from both:

  1. Forming
  2. Spreading
This is due to the rusting process slowing or stopping entirely.



1. They Protect The Entire Vehicle
2. Reduce Paintwork Oxidation - Meaning paint retains shine
3. Can Be Self-Installed
4. A One-Time Fit
5. No on-going maintenance time or cost
6. Last 10+ Years
7. Transferable to your next vehicle
8. Work on vehicles with or without rust


1. You Can't See Them Working
2. Don't Protect Against Surface Rust
3. Vary Widely In Quality and Results depending on the brand


Main System$500-800
Total Cost Over 10 Years$500-800
Cost Per Year (Averaged Over 10 Years)$50-80

Overall Verdict On Electronic Rust Prevention

Does Electronic Rust Prevention Work

The major benefit an ERPS system is the level of protection – offering full protection for your vehicle, top and bottom.

With minimal maintenance time and guaranteed performance an ERPS system could be the best fit if you’re looking for a ‘set-and-forget’ solution to rust.

The ERPS system can be self-installed to save on install cost or installed professionally. 

While this install cost may be more expensive, by installing through one of our registered installers, you will also get a 10-year corrosion warranty – guaranteeing no rust in your vehicle (conditions apply)

Ratings Explained:

Level Of Protection: ERPS systems protect the entire vehicle bottom and top – this includes areas that sprays can’t reach. 

Maintenance Time: Once fitted, there is no on-going maintenance required, other than checking the light on the system once a month. 

Install Time: This will depend on the type of system fitted and whether it’s installed by yourself or an installer or auto electrician. 

Total Cost: Depending on the type of system you get 

Maintenance Cost:  Due to having no sacrificial parts or wearing comonents. 

Install Cost:  Again, depending on the type of system fitted and whether it’s installed by yourself, a professional installer or auto electrician.

Can I Do Both?

Hopefully you have a better understanding of rust prevention and your options.

But you may be wondering – can I get both a spray coating and electronic system?

And Yes – you absolutely can.

A ‘combo’ approach is probably the best level of protection you can have – however, it may be necessary and will vary from person to person.

We recommend fitting an electronic system first – to ensure that you’re able to correctly install it (specifically couplers/pads placed underneath the vehicle)

Once you have the electronic system fitted, you can have the chemical spray applied and you’ll be protected both electronically and physically.


We hope that this has given you a better understanding of your options for rust protection on your vehicle and a better outline of the costs, maintenance and other factors.

We should note that this assessment is given as an educational guide and all data and information based on our research and findings.

If you’ve got questions about rust prevention or the best option for your vehicle – feel free to contact us via 1800 332 899 Monday Friday 8am-4:30pm AEST.

If you’d like a quote on an ERPS system for your vehicle, simply fill out your details below: