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Be sure to guard against rust -- and cut-rate jobs won't do

Rust is the No. 1 reason that most perfectly good cars wind up prematurely in automotive junkyards today. The scrap pile awaits and beckons your car if preventive action is not taken to halt the early normal stages of metal oxidation.

All US carmakers now offer a three-year, anti-perforation-rust warranty on their cars. Only American Motors, however, provides a five-year guarantee, using the Ziebart process.Even so, car owners should make sure their cars are thoroughly protected against corrosion, especially in the snow-belt states.

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In most cases rust has already attacked the sheet metal stored in the open factory yard. In other words, cars have actually begun to rust even before they leave the assembly line, despite the wider use of rust-inhibiting primers and zinc-coated steel.

Once the car is on the road, wintertime road salt can clutch the car's sides and underparts to speed up the rusting process.

"The speedup is so quick," says a report by an Environmental Protection Agency research team, "that last year over $2 billion in damage was rust on cars and trucks, sending them to the junk heap."

Arresting the progress of existing rust is your first step, since rusting seems to have gained a head start on new cars and continues at a fast pace from salted roadways.

Adding the cost of a complete protective undercoating to the price of a new car will generally provide some protection.

In other words, have the undercoating or sealing applied before the car leaves the dealer. Usually, new cars are shipped and kept off the roads to keep the mileage close to zero. Any road dampness on the undersides before the application of an undercoating can easily be trapped beneath the coating, allowing the rusting process to continue. If possible, then, supervise the sealing to make sure you have a satisfactory job.

An investment of about $50 gives an undercoating from bumper to bumper. A more thorough job, such as a Rusty Jones of Ziebart processing, costs several times more. Don't be fooled by an ad that blurbs: "Only $15.95 undercoats your car. Why pay more?" There are good reasons for paying more.

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A cheap job does not guarantee a complete job. The rocker panels -- metal beneath the door and the inside box construction that forms the frame of the unit body -- are not even touched in a cheap undercoating job. In time, moisture from these unprotected areas seeps under the car and begins peeling away the areas that do have undercoating.

Rust sets in and the exposed metal begins to erode from the inside out. Even a good undercoating job that has covered every inch of the car's underparts can crack and peel away. What chance do the undercoated parts have when moisture and dampness spread underneath them from the bare metal?

One way to preserve the damaged undercoated areas is to check the wheel housing and rocker panels occasionally, where water and mud are most likely to collect. Remove the caked road mud and recoat the cracked areas.

A sealing agent that eliminates hardening, cracking, and peeling is a paraffin base. The "never drying" materials look like the heavy grease covering originally used by the US Army Ordnance Department on all its vehicles. The sealing specifications call for more than 13 rust inhibitors, sealing the metal to keep water and dust out.

The cost is $90 to $100 but well worth the extra money in protection.

Another rust deterrent undercoating is an oil- or tarlike spray. It lasts only a short time, however, and is ineffective. All undercoating jobs eventually get old. The problem, then, is how to check and prevent rust from spreading on cars more than two years old.

Rust will very likely break through touched-up paint jobs. If you buy a used car, inspect it for rust spots and patched areas. In a month or two you can expect the rust to show through these blistered patched areas. If you touch up your car, take precautions. The proper way to touch up paint is to sand the damaged area down to the bare metal. Then apply a new coat of good rust-inhibiting base paint, followed by the final coat.

Wax applications twice a year and frequent winter washings to remove salt, snow, and mud also help to prevent rust. Washing with a detergent is fine if you remember that detergents are hard on wax. If the water beads, the wax is doing its job. If not, the wax is too thin for protection and a new wax job is in order.

Also, frequently washing your car is a good habit, anyway. A high-pressure water spray is more likely to knock off salted mud and snow. Thus, an automatic car wash can be a lot better for your vehicle than hand-washing it with a garden hose, unless you use a high-pressure nozzle.

When washing the car, pay attention to the parts you can't see. Open the hood and spray away the caked-on mud that builds up on the front and rear wheel wells. Keep water away from the ignition system, however. Also, during the winter months, snow, ice, and mud are bound to collect under the outside front and rear wheel housings. Watch how you chop and clean these areas, because you can easily damage the metal and accidentally knock off the undercoating.

Bumpers begin to rust from behind the outer surface. Keep the inner surfaces as clean as the shiny chrome outer parts.

The mechanical parts of your car can also rust. If you want complete rust protection, you need to care for the mechanical parts, too. Flush the radiator at least twice a year to check for rust flakes. It's smart to add a rust inhibitor from time to time. Periodically, check the differential and transmission.Also, the next time your car is up on a hoist for a lubrication job , inspect the underparts: muffler, tailpipe, shock absorbers, and crankcase.

Causes of rust are always at work. Trying to stop these erosive bandits is a never-ending battle.

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