This is why rust proofing is important for your undercarriage

Posted by REJEL on 2nd Oct 2023

The undercarriage of a vehicle forms the vital frame work that holds the wheels, axles, brake liners and exhaust stem together. Any damage to the supporting framework can affect the vehicles driving experience - never mind the costly repairs!

Frosty winter nights with salt gritted roads are notorious for the damage it can cause to older vehicles frequently driven through these conditions. Salt is hydroscopic meaning it attracts water and will continue to do so for as long as it is present. Salt speeds up the process of oxidation so the sooner it is removed the less chance it has of affecting the undercarriage. The rear and front axles, muffler, exhaust and transmissions are particularly vulnerable to corrosion and the subsequent damage rust can cause.

During the winter months frequent pressuring washing of the undercarriage will ensure salt is removed before it can have any long term damaging effect.

Rust proofing the undercarriage before winter is the best form of protection for frequently driven cars that are 5 years and older. Re-applying every 3 years will keep your car protected no matter what it's age.

Rust-proofing is the process by which waxes and oils are applied to prevent rust from forming. Improvements in automobile construction in recent years have diminished the need for professional rust proofing for new vehicles. But if you live in snowy, wet climates or you plan to keep your car for a long time, you might want to get your car rust proofed.

There is considerable debate about the need for rust proofing. But, for people who drive in cold climates and plan to keep their cars for more than five years, many auto-specialists do advise on getting rust proofing applied to help the important framework maintain it's important function for longer.

Rejel have made rust proofing any size vehicle more achievable for the DIY enthusiast with the availability of their rust proofing kits. These kits include all the products for treating signs of rust and protecting your vehicles cavities and undercarriage. If you just want to protect you undercarriage these are the three products we recommend and the features of each:

Dinitrol 4941 Black

  • Possibly the best known product in the Dinitrol range.
  • Very thick so it is advisable to warm prior to application.
  • One of the best salt spray tests on the market up to 1500 hours.
  • Self-healing when chipped or abraded.
  • Also available in brown/bronze (Dinitrol 4942)

Dinitrol 4941 application is much more controllable and doesn’t run. It is a black wax, so when applying to dark places such as the wheel arches it can be easy to miss areas. Using an inspection lamp will be handy - it will also help show-up thinly applied areas.

Dinitrol 447 stone chip                  

  • Dinitrol 447 is a fast drying, rubber and resin based stone guard.
  • It is particularly suited for areas of very high abrasion such as wheel arches.
  • The added advantage of using Dinitrol 447 is that it can be overpainted once it has thoroughly dried.
  • Dinitrol 447 is available in both black and grey and requires warming prior to application with a working temperature of 10 -15 degrees Celsius.

Dinitrol HP high performance wax                                                                                                                                                

  • Dinitrol HP is a good alternative to the other underbody wax products as it's transparent.
  • Once dried, it will resist temperatures of up to 180 degrees Celsius so it is ideal for use around a vehicles engine compartment.
  • It also has self-healing properties making it ideal for use as an underbody rust protective coating.

Prior to applying rust proofing it is important to check for and treat any signs of rust. Dinitrol rust converter RC900 is perfect for getting rid of patches of rust. This should be followed by an underbody wax, stone-chip or cavity wax depending on where the rust is. These Dinitrol products are available in aerosol cans for ease of use.

For spraying into box sections or cavities, then the aerosol spray extension nozzle is a handy addition. Dinitrol RC900 cures and dries quickly. 

The 'Dinitrol Corrosion Protection' video takes you through the different stages of rust proofing a vehicle. 

Steps to Dinitrol rust proofing application  

Why Dinitrol for rust proofing?

Waxoyl or Dinitrol products are often expressed through forum posts and comments as most used to protect the undercarriage of classic cars, Land Rovers, 4x4's, motorhomes, vans and trucks - for keeping the salt water away from the metal and treating any underlying rust. However, the Dinitrol products often comes up trump because of the extensive range of products for different applications - as well as the support service offered.

For more information, contact Rejel - the licensed UK distributor of  DINITROL to the UK market.

"I deal with Rejel often for Dinitrol products and I've never had anything other than excellent service. Orders are dealt with quickly and you're kept informed throughout the process. Can't fault them."

Customer Review submitted to Google on 07 November 2016.