---

Exposed Rust Still Creeps

By Cliff Leppke

Those self-appointed car experts, (you’ve heard them) tell us that new cars don’t rust. Vince Megna, a lawyer and author “Bring on Goliath: Lemon Law Justice in America,” says, “Rustproofing is nothing more than a modern day … secret potion in the traveling medicine man’s show. Technological advancement has virtually eliminated rust problems in today’s new cars.”

Not true: Heat, moisture and a catalyst, such as salt, help nature return metals, such as steel, into oxide.

While newer autos exhibit less exterior sheet-metal perforation and a superficial inspection of these cars would lead you to believe today’s cars don’t rust like old new cars, the nasty fact is corrosion still savagely eats, as Blondie sang, “Hondas and Subarus” and other cars, too. An auto’s sheet metal, despite numerous factory anti-rust processes, is vulnerable. One industry insider told me one car maker was using metal that’s more, not less, likely to rust. At first, I thought he was whining; he didn’t respect crash-absorbing, unit-body construction. Now as those cars age, I believe he’s right.

What You Can’t See Can Hurt: Corrosion is covered, and I’m not speaking about the warranty. For instance, plastic-fantastic body cladding, fenders, hoods and wraparound bumpers cover metal. Plus, gobs of chip-resistant body sealant—sprayed underneath the car and on rocker panels—hide the horrible truth—metal rusts. And because you cannot see rust, you probably won’t seek address under the vehicle’s rust-through warranty. Good for carmakers, bad for you—very bad. Corroding metal, covered by thick, chip-guard finish, actually rusts faster due to trapped moisture.

Worse than body disfiguring exterior rust-perforation is corrosion underneath the car. It attacks suspension mounts, floors and body reinforcements. A rusting undercarriage compromises structural integrity.

My camera found rusting not-very-old relics in my company’s parking lot. The rust-seeking quest wasn’t difficult. To wit: this Nissan minivan’s hood. Its top only hints at the dangers below. The entire front inner panel is, well, gone.
Additional find, not shown, is a 2000 Dodge Durango. Painted steel bumpers look like Swiss cheese, the rear lid’s inner and outer panels are puckered—a fault noticed during its two-year inspection—and the side quarter panels are perforated from the fender lip, where inner and outer panels are spot welded, migrating toward the side windows. A Dodge truck illustrates how discretely rust is disguised. Notice the vehicle’s tailgate. See that plastic panel? Look behind it. Rust is alive.

Ford Econoline vans, despite their much ballyhooed improved bodies, don’t fare well. For instance, this 1996 model, which was delivered in 1997, has holes around its body mounts, through the driver’s floor, part of the fire wall, lower rear quarter panels, and near the left seat belt mount. The insides of most doors are rusted. Look up. Large holes replace the “A” pillar, roof, gutters and side panel. Ford applies plenty of sealant, but it only hides the bubble-delicious frenzy underneath. Eventually, the caulk-like treatment pops off and the truth is told—where body panels join, rust attacks; when galvanized panels abut non-galvanized ones, such as the roof, there’s nothing but air.

Remarkably, exterior sheet metal—looks galvanized—rarely rusts where the paint is scratched. This is what leads experts to say cars don’t rust. But as the following examples illustrate, body cavities and sandwiched panels remain corrosion cauldrons.
GM’s mark is tarnished. For instance, GM’s rocker panels, floors and inner body panels vanish. This fuel filler is an example of how joined inner and outer rear quarter panels invite rust. A plastic fender covers perforated metal that surrounds this front spring’s tower. In fact, holes now replace metal where engine compartment wires and support struts formerly were screwed into the unit-body. Corroded ground connections and switches have stalled this vehicle.

Our last example is a 1995 Jetta (photos on Page 6). There’s rust where floor panels are welded to various other pieces. Sealant is the only thing that holds stuff together. The air conditioner’s condenser holder, a two pieces of stamped, spot-welded metal behind the front bumper is completely chewed away. A lower grille, mimicking a brake-cooling duct, hides this blight. Surprisingly, the front doors look rust free, but the rear doors’ inner panels have been mercilessly savaged by rust. This outer panel’s stains and bubbles are proof—a demonic rust strain is spreading.

Is rust proofing helpful? Yes. But unfortunately, application is everything. And that’s the rub. Most commercially rust-proofed vehicles I’ve examined, such as the Ford van depicted, aren’t rust proofed inside lower body cavities. Rust proofing was simply applied to the undercarriage’s exposed surfaces.

Rust proofing didn’t halt corrosion caused by this van’s poorly prepped metal or floor sections where multiple panels are spot-welded together. Yet, a proper rust-proofing job can improve a vehicle’s life.

I spray Wurth’s protective wax coating inside the engine compartment. Wurth’s inner-body panel rust proofing works elsewhere. This product prevents rust under a car’s hood or where emblems are attached. It is surprisingly good protecting fuel and brake lines. It even survives the tortuous environment found in wheel wells. It doesn’t prevent rust that’s forming underneath a vehicle’s undercoating—such as a Scirocco’s spot welded fuel system brackets or vulnerable areas were multiple pieces of metal are sandwiched (spot welded) together, such as the rear trailing arm’s body mount or double-wall floors.

Why Rust? For our purposes, I won’t make a distinction between corrosion and rust. There’s a difference. The reddish stuff found, say, on a piece of exposed iron is hydrated ferric oxide or rust. Aluminum, because it isn’t a ferric metal, doesn’t rust; it corrodes.

The Society of Automotive Engineers publishes papers that discuss rust, its causes and its prevention. Corrosion that afflicts cars includes a type caused by metal-to-metal contact and metal that is exposed to heat, moisture and a catalyst. The latter is usually salt poured on icy pavement.

What slows rust? Several rust-reduction methods can be found by surveying VW’s body-making practices. Until the early 1980s, VW relied on acid-treated metals (called etching), zinc-rich primers (paint) and sealant, such as undercoating. Its cars usually didn’t rust too quickly where salt wasn’t a factor. When VWs were exposed to salt, rust had a feast. One reason is that VW relied on body reinforcements, such as bumper supports, that were spot welded onto another panel. The two metals and a corrosive agent bred rust. Plus, spot-welding can damage a metal panel’s rust-protecting treatment.

Beginning in 1982, VW initiated its body protection program. The goal: reduce corrosion and improve car value. VW tried rust-reducing fasteners, inner fender liners, sprayed-on rust proofing, wax-coated body cavities and chip-resistant finishes on the newly designed Scirocco and Quantum. These methods slowed rust but weren’t perfect. For instance, rust would creep after it formed, spot-welded areas were vulnerable and some places, such as door reinforcements weren’t protected. For 1984, Rabbit (Golf) and Jetta bodies joined the war against rust.

At Audi, the company began constructing cars with galvanized steel. Galvanized steel has rust-resistant zinc treatment. It’s been used by other car makers—usually in rocker panels. Audi, however, innovated by using galvanized metal throughout the entire body, rather than a few selected panels. Wax-coated body cavities and spot applications of rust proofing offered additional protection. Audi’s engineers also improved metal fabricating techniques, such as crimping instead of spot welds.

According to my brother-in-law, these methods are effective. His Audi 90 Sport Quattro, which sloshes through the wintery Twin Cities, has impressive body life. Audi’s trim, however, could be better. For instance, steel inside rubber strips bulges and twists due to rust. Sometimes, trim chafes through body paint too. Yet, his decade old Audi casts a solid shadow.

VW, since the late ’90s, borrowed Audi-like rust protection. New metal attaching and shaping methods, such as tailored planks and rust-resistant fasteners, also thwart rust.

The gist is that many new cars have better rust protection than those made decades ago. Nonetheless, cars still rust.