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Rust Prevention Tips

Stop Rust before it Starts!

Rust It is unsightly, unsafe, and undesirable. And because no one wants to buy a rust bucket, it can radically depreciate your car's resale value. For those of us who buy used or own older cars, it is important to learn how to:

  1. find rust
  2.  keep it from starting
  3. and address it once it has started.

In order to detect rust on an unfamiliar car or combat it on your own vehicle, one needs to understand how rust usually starts and where it is most likely to emerge. And please do not believe all salespersons as the Corrosion Doctors keep telling you here:

How Rust Starts

The way rust usually begins is through the chips and nicks you receive from the pebbles and stones that pepper your car through daily driving. With a small nick exposing bare metal in an unnoticeable location, it's just a matter of time until rust forms. Left unchecked long enough it will eat its way through to the other side. When this happens you have problems because once a rust hole starts it can not be stopped. It can only be slowed down. Or at at least address it before it eats it way to the other side.

Where to look for Rust

The most likely areas to check for rust would be in and around the wheel wells and on the fenders immediately behind the tires. These are the war zones where your tires will kick up stones and chip the paint. The front of your car can also catch flying stones from other cars, making this a problem area as well.

If you are looking at a used car for sale, use a flashlight to look underneath the car behind the front and rear tires on both sides. Of course, before you do this make sure the car is parked on a level surface in park/gear and the emergency brake engaged! If it's on a slope, put blocks under the wheels for added safety. Shine your light on the inside of the fenders and wheel wells. Check for excess body filler, which from this side will look like hardened putty all globbed up. In areas where you don't have a clear view, use your fingers as your eyes and feel around. Do you feel globs of hardened putty under there? If so you're looking at a likely rust repair job.

Now you can use the sound test to decipher how far up body the filler goes. Above the suspected area, tap lightly on the car's body with your knuckles. You should hear a tinny metal sound. Continue tapping and move slowly down to the area in question. Does the sound change from tinny to solid and dense? Where the sound changes is where the filler starts.

Once you have detected a rust repair job you may want to stop your inspection and find a rust-free car because eventually the rust will come bubbling back up through the paint. The car may look great now, but if it looks like swiss cheese in a year, you'll be the loser in this deal.

Another word to the wise for the used car buyer: Avoid cars with fresh paint. Think about it. No one paints a car just because the color has faded a little. It was painted because it was either in an accident or it had a rust problem or worse yet - both! A body man can hide a lot of sin with paint and body filler. Be wary.

Other rust-prone places to check when buying a car, would be the exterior flooring under the driver's and passenger's seats, the interior flooring underneath the carpeting/matting, under the carpeting/matting in the trunk, and around the engine compartment. Use your flashlight, your eyes and your fingers!

How to Keep Rust from Starting

The key to keeping a rust-free car is by stopping rust before it can start. Or at at least address it before it eats it way to the other side. Because bare metal will oxidize and painted surfaces won't, you only need to protect your car from the elements to keep rust a bay. You should maintain your car's body just like everything else. This means a periodic checking of the most common areas where rust might rear its ugly head.

Keep some touch-up paint on hand and periodically go over your entire car's painted exterior with fine tooth comb. Look for chips and nicks in the paint. If you find a chip where surface rust has already weaseled its way in, use sand paper (220 grade or finer) and carefully sand it down to bare metal. Tiny nicks will be a challenge. Wrap the sand paper around the tip of a small screw driver and try not to mar the surrounding painted surface.

Clean the dirt from the chips with a rag dampened with mineral spirits and let dry. Using a touch-up brush, dab a little paint on the nick, just enough to fill in the gap. There's no need to coat the surrounding painted surface. Otherwise it will just make your touch up more noticeable. Do it right and your nick practically becomes invisible. If you botch up your first try just wipe it off with your dampened rag, let dry, and start over.

Periodical washing of your car's undercarriage is also a good way to protect your car from corrosion. Visit your manual car wash on a monthly basis and spray the underside of your car and inside the wheel wells too. A build up of dirt can hold moisture against your car's undercarriage and promote rust. Keeping it clean under there will allow surfaces to dry quicker making it less susceptible to oxidation.

Whether you are in the market for a used car or just trying to maintain your current set of wheels, practice of the following steps can keep rust from eating away your car as well as your pocket book.

National Motorist; The Steering Column, Winter '97


Prevent rust by keeping the underside of your car clean also. Place a lawn sprinkler under your car and turn on full blast. Move occasionally so it will reach all areas. This is a good way to remove all salt and road grime. (reference)

If you chip the paint on your car, clean promptly and apply touch-up paint or clear nail polish to the area.

If the carpet in your vehicle is subjected to a lot of salty water over the winter, rust could be forming where you can't even see it, underneath the carpet. A good rug shampoo, either a do-it-yourself project or professionally done, will help remove the salt from the carpet fibers. Be sure to clean the upholstery too.

Is Rustproofing your Car Foolproof?

by John Ewoldt, Star Tribune staff writer October 14, 1999

When Neil Young sang ''Rust Never Sleeps,'' he might as well have been croaking about the slow but inevitable deterioration of Minnesota automobiles. Because the state uses salt on its roads, vehicles can decline from showroom beauties to embarrassing rust buckets in a hurry.

For years, the easy answer to the deterioration was rustproofing. But for a variety of reasons, the rustproofing business isn't what it used to be. Lindsay Fraenkel, store manager at Ziebart in Minneapolis, says leasing has taken a big chunk out of his rustproofing business.

Even dealerships aren't pushing rustproofing as an option as often as they used to. Part of that has to do with cars being made with longer-lasting galvanized steel.

Manufacturers' warranties for protection against rust perforation also are longer. Most warranties provide corrosion coverage for five years, and some are even longer, such as General Motors (six), Mitsubishi (seven) and Volkswagen (twelve).

So is rustproofing a thing of the past, even in Minnesota? Star Tribune auto columnist Paul Brand still recommends rustproofing for new and used cars, especially for anyone who plans to hold onto a car for more than five years.

Cars don't generally show rust until after the fifth year, about the time many manufacturers' warranties expire. But consumers may be disappointed to discover the kinds of exclusions in corrosion coverage, including rust caused by ordinary elements such as sand and salt.

Examine the warranty for exclusions, such as surface rust, rust caused by industrial fallout, areas damaged by stones and debris, corrosion caused by sand, salt and hail and tree sap. Some warranties contain vague phrases such as "rust caused by abuse or misuse" or "lack of maintenance" that may prove to be catchalls to deny coverage.

Some people may be tempted to wait until the sixth year to have a vehicle rustproofed, but by then it may be too late for prevention; it could mean a body-shop repair instead. It depends on how the car has been maintained up to that point.

When should you rustproof? Generally, if a vehicle is new or less than three years old, it's a candidate for rustproofing if the owner wants to keep it for more than five years. Otherwise, a person may want to let the next owner worry about rust.

Is it worth it to rustproof a car that will be sold before rust starts? An after-market rustproofing may enhance the value of a used car somewhat. And most rustproofers will allow the warranty to be transferred to a new owner for the first five years.

Price and warranty

Rustproofing prices generally range from $200 to $300. Ziebart, with four Twin Cities locations, charges $280 to $310 for new vehicles, $240 to $270 for used ones. Falls Auto Clean and Rustproofing in Minneapolis charges $200 to $220 for most vehicles, plus $20 for an annual inspection. J. Brenna's Rustproofing in West St. Paul charges $245 for most cars and $295 for trucks.

Most new-car rustproofing comes with a lifetime guarantee that is good as long as the owner brings the car in for annual maintenance. At Ziebart, that means taking the car in every year, within 60 days of the anniversary date of the rustproofing job. Failure to have the car inspected within the 60-day period voids the warranty.

Not all rustproofers require an annual checkup, but be wary of those that do not. These inspections often catch areas that need to be retreated.

Some rustproofers charge a fee for the annual inspection.

When it's time for the annual inspection, ideally, the outside and underbody of the vehicle should be washed thoroughly (a run through a car wash may not adequately clean the underbody). Customers will want to feel for dirt under the wheel wells. Take a rag to rub out as much of the dirt as possible or use a high-pressure wand at a self-service car wash.

Ziebart doesn't charge for its inspections, but charges $40 for an outside and underbody power wash if the customer fails to do it in advance. Falls Auto Clean charges $20 per year. J. Brenna's Rustproofing requires an inspection every other year, but does not charge extra for it.

Depending on its age and mileage, a used car that is rustproofed may be ineligible for a lifetime warranty. Ziebart will warrant a used car for seven years from date of manufacture. B&K Auto Trim in Roseville will warrant vehicles for six years, provided they have less than 30,000 miles at the time of service. Older used cars in good condition with high mileage still can be rustproofed, but the warranty may be limited.


Some experts say that rustproofing can actually accelerate rust if done incorrectly. The companies mentioned have all been doing rustproofing for more than 15 years. Several methods are used.

Many rustproofers such as Ziebart use a wax and oil method that creates a tar-like coating. Others, such as Best Body Shop in Minneapolis, use an oil that seeps into seams to displace moisture. Falls Rustproofing doesn't drill holes but uses existing drain holes and a needle to inject a waxy material.

To get a sense for the quality of work, ask about the number of times customers have collected on their warranties. Nathan Slayton at Falls Rustproofing said only two customers in 28 years have had body work done because of rust. It's just as important for consumers to ask how often claims are denied because of exclusions that rustproofers have, such as "surface rust." Since rustproofers may not be as forthcoming about claims denied, consumers may want to contact the Better Business Bureau or state attorney general's office to inquire about any complaints or legal action filed against the company.

Reading the fine print

Once they've spent $200 to $300 for rustproofing, car owners might assume that any rust spots that appear would be repaired at no cost. But that's not necessarily true.

Surface rust, or rust "from the outside in," is not covered. Bubbling paint is probably not covered. If paint is blistering, the shop will sand it off and check the metal underneath. If it's silver in color, the peeling paint is not the result of rust, and is the consumer's responsibility.

Fraenkel, of Ziebart, says one of the best indicators of whether a spot is under warranty is how the body shop writes it up.

"If the estimate calls for a metal patch, that's usually going to be covered," he said. "An estimate that calls for sanding and painting indicates surface rust [not covered by warranty]."

It's important to find a body shop that shares your opinion of the repair. If the rustproofer allows you to take the vehicle only to its body shop, take it to several others anyway to build a case against the company in small claims court if a claim is denied.

Regardless of whether a car has been rustproofed, consumers can minimize rust by washing their vehicles at least once a month throughout the year and within a week of every snowfall. Next time the car is being serviced, ask the mechanic or a body shop employee to point out the drain holes in the doors, rocker panels and frame members. Check to make sure they aren't clogged. After the car is washed, run your hand along the lower third of the door panels to check for surface irregularities.