Which Rust Proofing Option is Right for You?

We reveal the four most common rust proofing methods available on the market. Find out which one is best for your car—and your budget.

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Rust proofing - winter road salt damage to car
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The Best Rust Proofing Options

Take yourself back a few months: you arrive at your dealership on a cold winter day to pick up the brand new car you bought, but the manager stops you. He suggests rust proofing your vehicle before you leave, and explains that it can be done right at the dealership, for a fee. You don’t want to absorb another cost, but the snow and salt-covered parking lot is making you think otherwise. It begs the question, is rust proofing worth it? With multiple rust proofing options available on the market, it can be a challenge to decide which one is best for you, if any. We’ve done some research on four of the most common car rust proofing methods to make that decision a little easier.

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Rusted car
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Electronic Module

One of the newest and most heavily disputed methods of car rust proofing is through an electronic rust protection system. Often sold by your dealer, an electronic module is a small device that must be professionally installed in your vehicle. These systems emit a weak current through a vehicle’s metal body, theoretically preventing it from reacting with oxygen and corroding. In practice, the effectiveness of these devices gets mixed reviews from experts and consumers alike. When compared with some of the latter methods, an electronic module is a far less invasive option for your vehicle, since no physical layer is needed to create a moisture shield for your vehicle. However, these devices can be significantly more expensive than their less permanent counterparts, ranging from $500 to $1,000 at a dealership.

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Cars on lifts at mechanic shop
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Tar-Based Spray

Also known as an “undercoating,” tar-based sprays were initially introduced in the 1950s to make car rides quieter. The procedure involves spraying a black, tar-like substance on the floor pans, wheel wells, and other exposed parts of the underbody of your car, which then hardens and acts as a permanent shield against moisture, salt, and other elements. Unfortunately, over time moisture can seep behind the hard outer seal and corrode the metal beneath. Furthermore, the rigid nature of a tar based spray makes it susceptible to cracks, which will pose an entrance for water to get in. For those that choose a tar-based spray, yearly inspections are required to reduce this risk. Ziebart is one of the largest providers of this method of rust protection and charges approximately $150 per vehicle.

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Best rust proofing - clean car undercarriage
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Dripless Oil Spray

Another Ziebart product, dripless oil has similar properties to a tar-based spray in that it hardens after being sprayed, creating a moisture seal for your vehicle. It has a firm waxy texture and clings to your vehicle’s frame without any run-off. Compared to its tar-based counterpart, a dripless oil spray covers more surface area because it’s applied to more interior regions of the vehicle, but this added protection comes with a price. The application process often involves drilling holes into the frame of the vehicle to maximize the area covered. If done by a trained professional, these holes are discreetly drilled and shouldn’t be visible. Additionally, these sprays will often leave smaller crevices and tight seams on your vehicle unprotected because of their high viscosity. Ziebart charges about $120 for a car and $140 for a van or SUV for this method, and it is recommended that it be re-applied annually.

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Rusted van
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Drip Oil Spray

Evident by its name, a drip oil spray is a more viscous version of the dripless oil spray. It’s applied in a similar fashion with holes being drilled into your car’s body. This procedure is the most common and most recommended method of rust proofing, as it’s able to fully rust proof your vehicle by penetrating all the small nooks and crannies. The biggest knock on this method is that the sprayed oil will drip off your vehicle for about two days as it dries. This means oil on your driveway. While this won’t damage your driveway, it will leave stains. As a result, it is often recommended to park your vehicle on the road while the oil sets. Krown charges about $120 to spray a car and $140 to spray a van or SUV. Annual reapplication is recommended.

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Is Rust Proofing Really Worth It?
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Is Rust Proofing Really Worth It?

Unfortunately, there is no simple answer when it comes to rust proofing your vehicle. To make matters even more complicated, it’s become a common practice for manufacturers to use galvanized steel in their vehicles frames. With a coating of zinc, galvanized steel doesn’t react with oxygen the way iron does greatly reducing the risk of rust. Cars built these days aren’t going to completely rust out like you’d see decades ago. Factors like the climate you will be driving in, the terrain you will be driving on and the amount you will be driving affect the decision. Rust proofing will make more sense if your vehicle is regularly subjected to the elements, but if you plan to mainly do city driving in a warm climate, chances are it isn’t necessary.

You should also take into account the length of time you will own your vehicle. Those with a short-term lease won’t see much benefit in rust proofing, save for a slightly higher residual value. If you plan on owning your vehicle for the long haul, rust proofing may contribute to maintaining your vehicle for longer. Finally, the decisions to rust proof has to make financial sense; you wouldn’t want to spend $1,000 rust proofing a $10,000 sedan.

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