Undercoating & Rust Proofing in Audubon, NJ

The short answer: a newer car you will trade in before its warranty runs out usually does not need undercoating, because factory corrosion protection covers those years. A car you are keeping well past the warranty, a pickup or body-on-frame SUV, or anything that already shows surface rust underneath is where it pays: an oil- or wax-based rust proofing applied in October or November, before the first brine, and renewed every year. Rubberized undercoating belongs only on clean, sound metal. Whatever you choose, have the underside looked at on a lift first, because no coating fixes rust that is already eating through.

The reason it matters here: every winter the underside of your car drives through the same brine the state sprays on the road. It hangs in the seams, pinch welds, frame rails and brake lines long after the snow is gone, and that is where South Jersey rust starts, underneath, years before it shows on a door or a fender. The simulator below shows how salt works on an underbody over a run of New Jersey winters, with and without a coating.

How New Jersey Road Salt Gets Under Your Car

NJDOT does not only spread dry rock salt. Its own winter FAQ says the rock salt is wetted with liquid calcium chloride or a salt brine blend to make it melt faster, and that the department pre-treats thousands of lane miles with brine before a storm starts. It can store up to 228,000 tons of salt at 68 facilities and just over 1,000,000 gallons of anti-icing liquid. County and town crews treat their own roads on top of that.

The liquid part is what matters for your car. AAA found that brines and liquid de-icers stay liquid longer than dry salt, coat components and seep into cracks and crevices where corrosion speeds up. In AAA's survey, U.S. drivers paid an estimated $15.4 billion in rust repairs caused by de-icing over five years, about $3 billion a year and almost $500 per repair.

The parts that take it first are the ones closest to the tire spray and the ones that hold moisture:

• Brake lines and fuel lines. Thin steel tubes clipped along the frame or floor. When NHTSA investigated brake-line corrosion on six million 1999-2003 GM pickups and SUVs, 85 percent of the complaints came from salt states, New Jersey among them, at 43.0 complaints per 100,000 vehicles against 3.0 elsewhere. Its 2015 advisory tells owners to wash the undercarriage often during the winter and clean it after winter, check the brake pipes, and replace the brake pipe assembly if severe corrosion is present.
• Rocker panels and pinch-weld seams. Two layers of metal pressed together, a natural trap for brine.
• Frame rails and subframes. Especially on pickups and body-on-frame SUVs, where the frame is exposed and boxed sections hold water inside.
• Fuel tank straps, exhaust hangers and suspension arms. Small parts with a big job; when they rust through, the part they hold comes loose.
• Inner wheel wells and body drain holes. The drain holes let water out of doors and rockers. Blocked holes keep brine inside the panel.

Undercoating vs. Rust Proofing: The Three Types

People use the words interchangeably. What matters is what is actually sprayed, because the three kinds of product behave very differently on a salt-belt car.

Oil- and lanolin-based sprays

Thin, soft coatings sprayed onto the underbody and into seams and cavities. Fluid Film is lanolin-based; Krown is an oil-based rust inhibitor. Because they stay wet, they creep into pinch welds and into rust that has already started, and they do not trap moisture behind a hard shell. The trade-off is life: they wash and wear off, most of all where the tires throw spray. Krown's own FAQ says an annual application provides 12 months of protection, and yearly reapplication is the norm for this kind of product. Expect some dripping and a light smell for the first days.

Wax-based coatings

A thicker film than an oil spray that firms up after it is applied. It stays on longer between applications in most spots and still creeps into seams better than a hard coating, but it wears in the areas that take the most tire spray, so those areas need a touch-up when the underside is checked.

Rubberized undercoating

The black, thick coating most people picture. On clean, dry, sound metal it is a durable barrier against stone chips and salt, and it deadens road noise. The risk is what goes under it. KBS Coatings, which makes coatings, puts it plainly: rubberized undercoating traps rust under one condition, when it is sprayed over metal that is not clean, dry and already sealed. Sprayed over existing rust or moisture, it seals the problem in and hides it, and if it covers the drain holes it keeps water in the panels. That is why rubberized coating belongs on new or fully prepared metal, and why we do not spray it over a frame that is already scaling.

Does Your Car Actually Need Undercoating?

The honest answer depends on the car, and a shop that does undercoating should tell you when you do not need it. Consumer Reports' short answer for new cars is no: cars are built with corrosion protection today, and it advises buyers to skip undercoating as a dealer add-on, which it put at about $800.

Where it earns its money in South Jersey:

• You are keeping the car well past its warranty. Factory protection ages, and every winter adds up. The years that count are years five through fifteen.
• Pickup trucks and body-on-frame SUVs. An exposed ladder frame and boxed rails catch salt that a unibody car sheds.
• A car with early surface rust you want to slow down. An oil or wax product that creeps into the rust is the right tool here, not a rubberized shell.
• A used car that spent its life in a salt state. Get the underside looked at before you decide what it needs.

Where to skip it or do something else first:

• A new car you will trade in before the warranty runs out. The factory protection covers the years you will own it.
• Heavy scale, flaking brake lines or rust-through. No coating reverses that. The metal needs rust repair first, and brake lines that are flaking need replacing, not coating.

When to Undercoat in South Jersey

Before the salt, not after it. The best window is October and November, on a dry day, so the product goes onto clean dry metal before the first brine run. If you missed the fall, the next best time is spring, after a thorough underbody wash that gets the winter's salt off, which is NHTSA's advice either way. Oil and lanolin sprays go back on every year; wax and rubberized coatings are checked each year and touched up where they have worn.

What an Undercoating Visit at AutoBlast Includes

It starts with the car on the lift at our Audubon shop on the White Horse Pike, so we see the whole underside instead of guessing from the driveway:

1. Underside inspection. Frame rails, rockers, brake and fuel lines, tank straps, exhaust hangers, subframe mounts and drain holes.
2. Honest call on existing rust. Light surface rust is noted, because the right product depends on it. Scale, flaking lines or rust-through are shown to you and quoted separately in writing as rust repair. Nothing gets coated over.
3. Clean and dry. Loose scale and road dirt come off and the underside is dried, because a coating is only as good as the metal under it.
4. Masking. Brakes, exhaust, sensors and anything that should stay clean are covered.
5. Coating. The underbody, seams and pinch welds, and the frame and rocker cavities where the product can reach.
6. Drain holes and walk-through. Drain holes are checked open, and we walk you through what we found and when the coating should be looked at again.

Every job is quoted in writing before any work starts, and if the inspection shows the car does not need a coating, we will say so. Call (856) 546-8880 to book a time before the salt season, or send us a request.

Undercoating Near Audubon, Cherry Hill and Camden County

AutoBlast is at 21 S. White Horse Pike in Audubon, a short drive from Haddon Heights, Oaklyn, Mount Ephraim, Collingswood, Bellmawr, Barrington, Haddonfield and Cherry Hill. The same shop handles the rust repair an inspection turns up, the exhaust and brake parts salt wears out, and the pre-winter detail that keeps salt off the paint.