Postimees · Cars & Technology (Auto ja tehnika) · 2025
Rust protection for your car – an investment, not a cost
English translation of the original Estonian article. Original headline: Auto korrosioonitõrje – investeering, mitte kulu
See the original design in the magazineAlthough new vehicles leave the factory with better protection than the Ladas or Zhigulis of old, a sneaky enemy may still lurk beneath a beautiful surface: corrosion. In a Nordic climate, a car's lifespan depends largely on how successful the battle against rust is. In conditions where winter brings plenty of snowy slush and salt to the roads, the topic has to be taken seriously.
Corrosion is not merely a cosmetic problem. By undermining critical chassis parts, it eventually threatens both your wallet (through falling resale value) and something far more important – personal safety. But how do you choose the right expert to fight corrosion, one who will make sure your four-wheeled friend serves you longer and keeps you safe on the road? Advice comes from experts in the field: Andrus Aasamäe, head of ARS Autoteenindus and master bodywork technician, and Margus Tammsaar, CEO of Krown Eesti.
How does corrosion, the vehicle's enemy, actually develop?
Corrosion, or rusting of metal, is an insidious destructive process that affects a vehicle's lifespan and safety. This electrochemical reaction weakens the metal. Rust formation requires three basic elements: metal, oxygen and water/moisture, i.e. an electrolyte that accelerates the whole process.
For vehicles in Estonia and other Nordic countries, however, corrosion is an even more pressing issue, because a powerful catalyst is added here: salt. Spread on the roads, salt solution is like a "turbo engine" for rust, because it is a strong electrolyte. Salt-enriched water (of which there is plenty on the roads in winter) multiplies the movement of electrons on the metal surface, intensifying the corrosion process even further.
As a result, salts penetrate metal surfaces and accelerate rust formation, making our climate one of the "most favourable" environments for vehicle corrosion. That is why rust protection in these conditions is a necessity rather than a luxury.
When is the right time for treatment, and how often?
Experts believe that rust protection makes sense for both new and used cars. Ideally it should be done right after purchase to protect cavities and inner surfaces that factory technology mostly doesn't reach. This prevents rust from forming before it can even start. As a rule, a new car's warranty remains valid even if the service is bought outside the dealership.
"With used cars, rust protection significantly slows down the ongoing process and protects areas not yet affected. Of course, it's important to remember that if a vehicle already has heavy rust on body parts or holes in the floor, the parts should naturally be repaired first and then treated," Tammsaar emphasises.
"We recommend anti-corrosion treatment every two years if the vehicle is in normal use," explains Tammsaar, adding that regular repetition ensures the protective layer keeps working. Aasamäe adds that if you drive on very muddy roads or even off-road, it is worth treating the car every year.
How to choose the right service provider?
Since rust protection is an investment, it is worth choosing carefully. It is always sensible to research the workshop you plan to take your vehicle to and ask the following questions:
What is the preparation process? Is the car washed, are the underbody covers removed, is loose rust cleaned off and is everything thoroughly dried? Preparation is the basis of a quality result!
What substances are used for rust protection?
"When choosing a service, it's important to pay attention to a number of details. You should check the number of work stages and what exactly is done in the process. For example, whether the underside of the car is washed properly, how much of the car is disassembled so that the rust protection can also reach behind covered surfaces, which areas are treated, whether two layers or one layer of anti-corrosion agent are applied, and so on. You should also ask the service provider whether additional holes are made in the body so that the agent can reach everywhere," explains Aasamäe of ARS Autoteenindus.
Why can prices vary so much between service providers?
Since there are service providers here and there, you have to look critically at what a given company actually does under the name of rust protection. Price differences are created by materials, quality and the number of stages in the service.
Some companies offer only a spray-over with a simple anti-corrosion agent, while others carry out a much more thorough cleaning before even getting to the main work process. This ensures a longer-lasting result, so that the investment can be justified.
The highly experienced Andrus Aasamäe of ARS Autoteenindus says that what matters is not only visible rust: great attention must be paid to the so-called hidden surfaces of the chassis. The inner surfaces of frames, for example, rust mainly because of dirt and moisture that collect there over time. "For example, SUV frames have several side openings where mud can get in, but the openings at the bottom are too small for the dirt to come out on its own. Mud that gets inside the frame binds and holds moisture well, which in turn accelerates corrosion even further," explains Aasamäe.
To do quality work, the underbody plastics and other parts must be removed, and then the underside of the car and the wheel arches washed thoroughly. "Only after complete drying can a rust converter, penetrating oil and finally underbody protective wax be applied. To achieve the best possible result, three protective layers are needed," Aasamäe explains the whole work process, adding that quite a few service providers don't offer such a thorough service, which may mean a lower price but also a poorer result.
With SUV frames, especially those used on muddier roads, rust protection has to be particularly thorough. "To wash out dirt that has collected inside the frame, a special car frame washer can be used, with compressed-air cleaning in addition if necessary. Then the inner surface of the frame is dried and coated with penetrating oil. Only after drying is a wax-based anti-corrosion agent sprayed inside the frame at high pressure, adding an extra rust-inhibiting and water-repellent protective layer," Aasamäe points out.
A car owner's checklist: what can you do yourself?
Although specialist treatment is paramount in the fight against corrosion, owners can also take care of their car every day.
Margus Tammsaar, CEO of Krown Eesti, explains that regular washing helps prevent corrosion. "It makes sense to wash your car in winter too, to remove as much salt residue as possible. Washing the underside is important, but unfortunately it's already harder to find as a specialist service," says Tammsaar, emphasising that removing salty mud from the entire car is extremely important in fighting corrosion.
Some car owners may consider doing rust protection themselves, but good results require the right conditions: a dry and warm place, a lift and proper tools. "The underside, and especially the subframe, is very hard to wash with home equipment; this work is best left to professionals who have special tools for it," adds Aasamäe. In terms of quality and coverage, a professional service does indeed seem the more reliable and sensible choice.
In conclusion, rust protection is an important investment rather than a cost. It makes sense for both new and used cars. When choosing a service provider, it is important to ask the right questions. You can take care of your four-wheeled friend yourself by washing it regularly. Constant and proper care is the basis of a vehicle's long-term reliability.