But while rust isn’t the problem it used to be, some motorists are still looking for added reassurance.  

There are two common types of aftermarket rust preventative systems.

  • The one favoured by vehicle manufacturers and much of the aftermarket is a chemical barrier that seals the metal against moisture and air that could start a rust reaction.
  • The other alternative is known collectively as electronic rust preventatives.  

Chemical barriers:

  • Involve spraying a waxy material inside the vehicle’s panels and body cavities to seal the metal against moisture and air that could start a rust reaction. 
  • It has been used for many years and is the one favoured by vehicle manufacturers.
  • It is best applied as the vehicle is being built but can also be used successfully afterwards.

What are the downsides of chemical barriers?

  • The material can have a slight odour that can take a few weeks to dissipate. 
  • For aftermarket applications it is necessary to drill holes in some inner panels to introduce the spray. These are closed with plastic plugs when the process is completed. 
  • Excess material may drip from unsealed seams for a few days after application.
  • There will be some places, such as inner roof panels, that cannot be treated due to restricted access.
When selecting a rust proofing provider look for operators that use products complying with Australian Standard 2662.1 Corrosion inhibition (rust-proofing) - Motor vehicles - product, and who apply the material in accordance with AS 2662.2 Corrosion inhibition (rust-proofing) – Motor vehicles – treatment of vehicles.

Electronic rust preventatives:

  • The makers of electronic systems give various explanations about how their products work and why theirs is better than others, but all claim that the vehicle is protected from rust by some electronic means.
  • At least one vehicle manufacturer is concerned at claims that some devices send an electronic pulse through the vehicle and that such pulses could interfere with sensitive vehicle electronics.
  • Anyone considering the purchase of such a device would be well advised to seek the opinion of their vehicle’s manufacturer or distributor (not a dealer) about the possible implications.
  • In 2015 two Australian distributors of electronic rust preventive systems were ordered to remove products from the market and refund customers who had purchased them. 
  • The action was initiated by the Western Australian Department of Consumer Protection, which “…sought independent expert opinion and testing, which concluded that Computerised Electronic Corrosion Inhibitor Units did not prevent rust or corrosion”.  For further information see:  https://www.commerce.wa.gov.au/announcements/red-light-distributors-car-rust-reduction-devices-ceci-units
  • At the same time the New South Wales Department of Finance, Services and Innovation warned consumers “… not to waste their money buying computerised electronic corrosion inhibitors for motor vehicles”.  For details see: https://www.finance.nsw.gov.au/about-us/media-releases/no-rust-bust-warning-re-car-rust-reduction-devices  


  • When choosing a rust proofing system always ask for a copy of the warranty document and look for any exclusions or conditions, such as regular inspections etc., that must be complied with to maintain cover.
  • Chemical treatments may exclude certain areas of the vehicle body, such as inside roof panels, from cover due to the inability to treat such areas without extensive dismantling. 
  • Look for warranties that commit to repairing any rust that appears in the protected areas.
  • Warranties that simply offer to replace a faulty electronic unit or retreat affected areas have little real value if the vehicle is already rusting.
  • Vehicle manufacturer rust perforation warranties will cover correction of rust areas, however the addition of another coating or system may lead to a dispute about who is responsible for correcting a problem.

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