3 March 2015

The Endless Quest for Effective Rust Prevention

The automotive industry has come a long way when it comes to protecting its new vehicles from the ravages of rust. Better galvanizing and preventative coatings have, said Mike Quincy, an automotive content specialist at Consumer Reports, caused rust to nearly disappear from the list of reliability issues that once plagued even newer cars.

But anyone who has ever owned an old car or truck knows that rust, or the potential for it, lurks in all of a vehicle's dark corners and crevices. What starts as a light orange frost one season can turn into bubbling paint another, flakes another, then, finally, the dreaded assault of what many refer to as "cancer" – holes.

Having purchased an Arizona-fresh 1987 Subaru GL wagon last year, I knew that if I didn't do something – anything – to prevent the humid, salty air of summer and the salty springtime road film that inevitably finds its way into everything in New York City, that the wheel wells on this thin-skinned Japanese car would quickly come to resemble a piece of burnt toast with large, ragged bites taken out of it.

There are many ways to keep a vehicle from rusting – keeping the paint touched up, washing the undercarriage frequently and avoiding driving on salt-covered roads or in any kind of moist weather. But for tips on further prevention, I explored the nearly endless array of options available on the internet. Some products were just for the wheel wells and flat undercarriage parts. Others could be sprayed inside doors and other cavities where corrosion-causing moisture might collect.

Finding the "best" one is a nearly impossible task, as there are so many options.

The guy in one YouTube video shouts the merits of spraying rubberized undercoating beneath his '69 Plymouth Roadrunner. But others online say that rubberized undercoating can cause problems if there are any gaps at all. Moisture and salt can build up in cracks and damage the metal underneath. The same can be said of factory-applied rubberized undercoating. I've personally seen unnoticed cracks in undercoating gain attention only after becoming gaping rust holes.

Some rust-preventative paints are, as advertised, hard as a rock when they cure. But after using POR-15 on an old Toyota several years ago, I learned that unless it was applied absolutely perfectly, it would peel in places, leaving patches of metal open to corrosion. Painted-over nuts and bolts disturbed the integrity of the paint's surface when they were removed — another drawback.

So I kept searching, and found that many people recommended wax or oil-based chemicals that could be sprayed into tight corners every year and allowed to drip down through doors and inside body panels. Eastwood was one of the ones noted as an effective wax product, and Krown, an oil-based spray inhibitor available in Canada, was frequently lauded by the chorus of unqualified internet commenters. Not many among this electronic peanut gallery seemed to like Ziebart, which makes a harder waxy undercoating.

Further digging revealed that many school districts in Upstate New York use Carwell, the American version of Krown, on bus fleets. The United States Marine Corps Corrosion Prevention and Control program uses it on a number of its truck and equipment fleets, albeit in conjunction with other products. If it worked well on heavily used fleet vehicles operating in a part of the country where road salt can make a car's body panels resemble Swiss cheese in only a few years, I reasoned that it might be just the stuff I was looking for to protect my "new" Subaru from the ignoble fate suffered by other old cars I've owned.

Peter Marini, head mechanic of the Fairport Central School District, near Rochester, N.Y., said that before the district's entire fleet was being serviced with Carwell's spray-on rust inhibitor every year, his shop had to repair wheel openings, stair wells and doors on buses on a regular basis.

"When I started here, we had just started doing buses with the Carwell product," he said. "On half the fleet, we'd be replacing panels all the time. To date, I don't do any rust repair, and we're talking 16 years."

Tom Delavan, Carwell's fleet manager, said the company serviced about 115 buses for Fairport annually, as well as buses for other school districts, fire trucks and military vehicles at Army and Marine Corps units around the region. Carwell's largest fleet, he said, consisted of about 120 buses at the Rush Henrietta School District, located not far from Fairport.

"The service life for a bus is 10 to 11 years," said Kurt Gerould, Rush Henrietta's head mechanic, who has had Carwell treat the buses in his charge for years. "But in 10 to 11 years, we don't have to replace body panels and parts because they don't rot out the way they used to. It's been a cost savings just in that."

Mr. Delavan said Carwell serviced about 3,000 vehicles per year in its retail service bays, which are located near Buffalo, N.Y. He said the company also treated about 3,300 fleet vehicles with its mobile units – an armada of trucks and vans equipped with portable air compressors, tanks of rust inhibitor and two- to three-man crews. He said they serviced roughly 200 school districts, 150 highway departments, 16 fire departments and several equipment rental operations, too.

The rest of the company's business comes from direct sales of its rust inhibitor products, and from application equipment employees fabricate at the shop in Buffalo. Mr. Delavan said those products were usually bought by classic car owners, "regular" car owners, fire departments; anyone who needed to keep a vehicle from rusting.

Bernard Friend, the operations manager of the the Marine Corps' corrosion control program, said that although the Corps does use Carwell's T32 rust inhibitor on a number of its trucks and other "assets," the chemical is part of a larger rust prevention strategy designed to reduce equipment costs by making things last longer. The suite of products the Marine Corps uses includes paints, primers, corrosion inhibitors, desiccants, film coatings, polyurethane coatings, and various tarpaulins and covers.

"There's a tremendous laundry list of products we apply to equipment," he said, adding that the Marine Corps has a process for testing the effectiveness of different products before they're put into use. "Paint protects a surface more than any inhibitor could, but the inhibitors get to the seams and crevices, and on removable parts."

Along with products from 3M, Sherwin Williams, Hentzen Coatings and others, Mr. Friend said Carwell's T-32 was an effective rust inhibitor.


Armed with all of this information, I decided that, for me personally, the best course of action concerning my rust-prone Japanese wagon would be applying Carwell's inhibitors at home. The problem – Mr. Delavan and the online opinionosphere were in agreement about this – was that it wouldn't do any good if improperly applied.

"This product is only as good as its application," he said. "If you're not putting it where you need to put it – inside doors and rockers and such – it's not going to be as effective."

Unfortunately for me – and for anyone who lives in a place where the highway department uses salt on the roads in the winter, or places further east and south, where the air is salty and humid – Carwell's retail locations are centered around Buffalo and Syracuse. That is not at all close to many places – the entire Northeast, the Midwest, the Atlantic and Gulf Coasts and mountainous areas all around the country – where rust is a problem.

And the company's mobile trucks don't make house calls – they service fleets.

The only thing to do, I reasoned, was to become a trained technician so that I could spread the knowledge of how to properly treat a vehicle to those who lacked the time, money or wherewithal to drive to Upstate New York. So I took one for the team and drove seven hours there and seven back in one day, spending several hours with Mr. Delavan learning how their product works and how to apply it.

Ken Wild, Carwell's general manager, explained that T-32, which has been deemed by the authorities as environmentally safe, is basically a penetrating oil. Once sprayed onto a piece of metal, it creeps into areas that haven't yet been treated, oozing into corners and crevices, displacing moisture and salt, and working its way around existing rust to bond with unoxidized metal.

Mr. Delavan showed me how to do the spraying, which was pretty straightforward. Here's how it's done:

Suit up in clothing you don't mind getting dirty. T-32 is oily, and gets all over everything. It's a good idea to wear a dust mask to keep vapor out of your nose and mouth. Safety glasses, although advisable, make it difficult to when spray gets on them (if you get this stuff in your eyes, it blurs your vision until you blink the oiliness away).

Open the hood, tailgate or trunklid and all the doors.

Drill small holes in the jamb side of each door, and in the door sills for access inside the rocker panels.

Use a long wand attachment to spray inside the doors and rocker panels, making sure you see "smoke" (atomized oil) start to billow from cracks on the other side of the door, tailgate or panel. Spray the seams around all the doors and tailgate/trunk lid– Carwell says T-32 will creep between them. Make sure to spray under the fuel cap access door, if the car is equipped with one.

Spray inside the wheel wells: Make sure to get around the edges, and up where the shocks or struts are mounted.

Use a flexible hose attachment to spray inside the spaces in the bottom of the hood, watching for smoke to emerge from the opposite ends of where you're spraying. There are many places for moisture to collect in there.

Spray around the sides of the engine compartment, behind the lights. Don't worry about getting it on wires, as Carwell says it will seep beneath the wire casings to prevent corrosion. Be sure NOT to get it onto engine drive belts and tires, as it is very slippery and, as Mr. Delavan said, would "make the belts pop right off."

Pop plastic plugs in all of the holes you have drilled.

Raise the car and begin spraying the bottom. Start with all of the holes and cracks that can be seen; anyplace where moisture could hide. Move from the front to the back and systematically shoot every hole. Then, start back at the front and spray the entire bottom of the car, moving toward the back.

Then you're essentially done. The outside of the car gets washed (to get rid of the oily residue). The car will drip for a few days, so it's probably not a good idea to park it in your garage or driveway, but Mr. Gerould says that even though his dripping buses cause a mess, the stuff washes away after some wet weather passes through. (Carwell's own facility, which never gets a reprieve, is perpetually slippery).

Whether or not my old Subaru will rust after a winter driving on salty roads remains to be seen, but the locks and parking brake cables, which were a little stodgy after 27 years in the Arizona desert, are already working a lot better. It's basically as if someone PB-Blaster-ed my whole car.

The downside, other than the mess, is that Carwell recommends applying T-32 every year. At a retail location, that costs a little over $100 for a normal-sized car. It's cheaper to do it yourself, but you need an air compressor and some sort of spray gun. Mr. Delavan said that a $20 paint sprayer from Harbor Freight Tools would work fine, but recommended Carwell's more complicated (and accordingly more pricey, at nearly $500) sprayer pot for more thorough application to the insides of doors and rockers and inside cab corners and such.


The bottom line of all of this is that rust prevention saves money and time in the long run. Everyone I talked with – bus mechanics, the Marine Corps rust prevention people and even a guy who owns a yard full of rusty Subaru parts in Connecticut (and first got me thinking about this) said that keeping rust at bay will make your machine last longer, whatever it is.

Of course, Mr. Quincy's practical advice for those who wish to avoid dealing with the headache and expense of rust repair is simple: Don't buy rusty cars and don't drive old cars during the winter. Easy, right?

Rust in the United State Infographic

27 Reader Comments

  • 1
    Marty SoCal March 4, 2015 at 16:09
    In the 500's and 60's, my dad, who was from Chicago, used to use the old engine oil from his last oil change before winter and an old fashioned bug sprayer to coat the underside of his cars! Lucky rusting isn't much of a problem here in SoCal (Except near the beach)
  • 2
    Dan Marinola Buffalo,New York March 4, 2015 at 17:21
    I have had Carwell applied to both of my everyday vehicles and am glad I did. The winter here this year has been bad and so far Carwell has protected them both very well. I highly recommend this process and product.
  • 3
    william mangan Brick N.J. March 4, 2015 at 17:57
    Where can I get info on buying this product, or getting it done? (Editor's Note: Visit http://www.carwell.com/howitworks.htm for more information.)
  • 4
    Joe Virginia March 4, 2015 at 18:41
    What do you think of this product? Please evaluate, let us know what you think. http://crcindustries.com/auto/?s=03282
  • 5
    Joe Virginia March 4, 2015 at 18:42
    What do you think of this product? Please evaluate, let us know what you think. http://crcindustries.com/auto/?s=03282
  • 6
    william merrick northern michigan March 4, 2015 at 19:09
    I have seen the effects of road salt for decades and the only answer is don't drive in the winter in northern climates(midwest).This article is basically by a novice and he really doesn't how the frame and brake/fuel lines and suspension parts are affected.The body mounts are a really weak point that's not addressed.Rustproffing is really a waste of money.Best bet-buy a rust free southwest car,buy a "winter beater" to best save your time and money.
  • 7
    Steve Calgary, AB March 4, 2015 at 20:37
    I'm in the process of restoring my 77 Mini, and had been considering different options to rust proof the under carriage and the interior floor (the real source of most under carriage rust). I decided to go with truck bed liner. It doesn't have the peeling issue, it's super tough, and completely weather resistant.
  • 8
    Chris Campbell Traverse City, MI March 4, 2015 at 22:04
    I've used Boeshield, a waxy spray product available in aerosol cans, to protect the usual rust locations on my Ford Ranger pickup. I drilled a couple holes from inside the bed to get the area over the rear wheel wells and plugged them with plastic plugs from the hardware store.
  • 9
    marty Long Island new York March 4, 2015 at 22:09
    I thought this was very informative and interesting article.
  • 10
    Jim Calgary Alberta Canada March 5, 2015 at 13:13
    Hi. Is there anyone in western Canada that applies T-32? Thanks
  • 11
    Tom J. Niagara, ON March 5, 2015 at 16:46
    The camps are all over on how to protect our cars. I personally like the oil based products like Krown Rust Control. It has very good creep action into areas we could never dream of getting into with paint or wax based products. I have used the wax based which cause more rust in my opinion once they dry up are are applied too thick. Ziebart and any asphalt based products I do not like once the moisture gets behind it will prevent the moisture from getting out. Ziebart was a great product at the time and may vary well be still but it will never see the underside of my classic car again. POR 15 if not applied correctly will peel. I agree with Lee Kipps opinion and comments on that. It is costly though and has a short application time so for the DIY guys it can be tough to apply properly. Most importantly is everyone needs to protect themselves with proper attire & respirators whatever product they apply. We need to be able to enjoy our classic for years to come after doing the job which ever technique you choose to use. Have a great day everyone!
  • 12
    Kevin NY March 5, 2015 at 06:28
    Exactly why the cars stay in the garage from the first snow until AFTER the first heavy rainstorm in the spring.
  • 13
    David Lawicki Rapid City,Mi March 5, 2015 at 09:14
    Sad to see Hagerty post something about rust prevention and not say anything about Ziebart rust proofing. The inventor was Kurt Ziebart who passed away 2-3 years ago out side off Traverse City.My first job was at Ziebart in Toledo,oh 1974.The yellow plug for Ziebart was introduced in 1964,it for warranted for life of the car not to rust out,black plug had grantee. Google Ziebart for history of company,
  • 14
    Ron Dee Michigan March 5, 2015 at 10:21
    I have heard that automotive company's void warranty's when any rust proofing is used?
  • 15
    Ron Dee Michigan March 5, 2015 at 10:22
    I have heard that automotive company's void warranty's when any rust proofing is used?
  • 16
    Lee Kipp Riverdale, NJ March 5, 2015 at 10:29
    I can't help but respond to your comment about POR15. I'm a sales rep for Absolute/POR15. Did you use our 2 prep products to properly clean the area of contaminants and impurities (like salts, chlorides, oils) and then etch it with our Metal Prep product. Our directions are very clear, for any effective paint application, prep is 90% of the work. You can't just paint a product on a contaminated piece of metal and expect it to stick. Our product is designed to be applied direct to metal or rust, and when properly prepped, it won't come off at all. You can pound it with a hammer and try to scratch it, it won't release from the substrate. If it came off any section, it was due to a surface contaminant on the metal or in the pours of the metal and if it were effectively cleaned and etched with our prep products you would never have had a problem. I'd be happy to send you some product to attempt to fix that area at no charge, even though your article didn't say nice things about my product. I look forward to your response.
  • 17
    John aulicino Rayland Ohio March 5, 2015 at 11:05
    Has mr. Quincey of ever seen a late model pick-up truck from anywhere in the mid-west? The statement that rust has nearly been elimated is so ridiculous, within three to five years nearly every truck around has a least bubbles on the cab corner and bed sides if not full blown holes. Some one should hold the auto makers accountable for building this garbage.
  • 18
    Calvin H. South Louisiana March 5, 2015 at 12:23
    Ref. rust-proofing 101 by Benjamin Preston. You may want to look at Boeing Aerospace product at: http://www.experimentalaircraft.info/articles/aircraft-corrosion-protection.php
  • 19
    MYTFAST Maryland March 6, 2015 at 14:41
    I learned at an early age & when I first started buying cars in the 60's that door bottoms, rocker panels & rear fender bottoms were the areas that always go first. WHY?? poor drainage if the number one cause. The little slits the put in the bottom of doors that also have a rubber piece along the bottom cause debris that works it's way into the door via the window glass creates a sludge dam in the door panels that stays wet for long periods of time which invites rust to form internally that is usually not recognized until it perforates the exterior paint surface. For every car I have I've drilled at least 4 large additional holes spaced along in the bottom of the door panels & paying special attention to the far end corners of each door which is usually beyond the factory drain slits. I also remove any rubber from the slits and then take a small paint brush and work a similar colored paint into the holes I 've drilled to coat any exposed new metal. On older cars, I will remove the door panels & hose out the door interior before the drilling & painting process. I door panels with existing rust, I reach into the door panel with a small wire brush, then rinse, then treat with navel jelly, then rinse again. After this dries, you can pore a high quality gloss enamel paint into the inside lower area of the door panel along the entire length & allow it to drip out the drain holes you've drilled. This ensures a smooth dirt resistance coating along the inner door. On doors with heavy existing surface rust, I've used mixed liquid fiberglass epoxy instead of paint for a super hard interior coating. The same hole drilling process can be used on lower rear fenders whose inside can usually be accessed from inside the trunk for the paint pour process. In all cases, be sure to place something under the areas below the drip holes to catch the drips. I've also found that opening the front door & regularly directing a stream of hose water in the space where the front fender meets the front door will keep debris from gathering & rusting he lower front fender area. For areas in the hard to reach areas under the hood & rear trunk/tail-light areas that a regular squirting of WD-40 will keep things rust & squeak free. WD-40 is one of those really great all purpose products that most people don' think about.
  • 20
    Robert White House, Tn. March 6, 2015 at 10:17
    Im originally from the north east. Does anyone remember the undercoating company Rusty Jones? I've seen the yellow waxy type product but I think the Rusty Jones stuff was red. I was surprised the product in the article needs annual re-application. Most othes are "one and done".
  • 21
    Wayne Bennett Ontario Canada March 6, 2015 at 10:45
    I once bought an old dodge pickup truck just for bangin around town and yard work...this thing was rough,lots of rust,in fact I had to make some new floor sectoins for it...any way It had a rather serius oil leak at the valve cover {old slant 6} after I fixed the oil leak I crawled under this wreck and noticed everywhere the motor oil leaked the metel and parts in that area were a gunky mess but after power washing the entire area I discovered everything looked like new...then a light went on in my ol 1947 brain...motor oil or any lubricant is a fantastic rust inhibiter...now I'm a believer in rust protection!!!
  • 22
    tom winnipeg and calgary alberta March 9, 2015 at 21:40
    i agree with the engine oil spray,if you have a gravel driveway-- for spills .in the 50 s,i brush undercoated my morgan with a chromium based paint i used the last half gallon in 1970. 200000 miles later in 2012 idid a complete rebuild and no rust at all undercoat still there but i could no longer get the product
  • 23
    steve isard Ontario , Canada March 12, 2015 at 20:11
    Most rust proofing materials are great, as the man said its only as good as the application. I have a 66 Plymouth that was Zeibarted when new, the doors still have no rust. The problem with yearly application is buildup of product. I live on a gravel road after 5 years there is so much dust collected that moisture is able to get under the protection, beware! Every hole that you drill will break the paint seal, just check around those plastic plugs every year. the plastic plug will hold the moisture. Best bet is to remove all door and tailgate panels. See where you have sprayed and thereby avoid window tracks and window regulators to ensure warranty if problem arises. Remove any plastic panels under the car for complete application, the marketers won't due to time costs, that why they just drill holes.
  • 24
    Harry Spieker COLUMBUS, OHIO March 31, 2015 at 08:51
    Owner - 1930 Model A Ford. I have a concern about getting Carwell T-32 on the wiring harnesses & connections. Any comments?
  • 25
    CORVAIRWILD/UGLYTRUK Uppa US April 2, 2015 at 08:13
    Carwell Krown is junk, I had my rust free (west coast) K5 Blazer done THOROUGHLY in Montreal, and it evaporated off the inner fenders after one week. I called Krown in Toronto, and they said it was invisible protection, so I guess the rust after one winter season was invisible too? I subsequently sandblasted alot of the ever expanding rust and painted and Fluid Filmed the ENTIRE underbody, as I have also done to my other vehicles that I've driven back from Arizona. FF has its limitations, and a thicker version is needed in wheelwells. FF also sells the needed sprayer and hoses etc in a variety of kits. Annual touch up is required in road salt wash areas. Amsoil also sell Metal Protector-MP, which dries a bit more and is tacky. The Fluid Film is animal based, no harmful to rubber moldings-petroleum distillates, and the FF DOES NOT DRIP!!! I've tryed a number of compounds, and have posted videos on ytube under CORVAIRWILD. Feel free to contact me or comment on the vids. I live deep in the salt belt and video the effects of unprotected cars and teeruks very often, as well my Fluid Filmed vehicles including the sandblasting of my Blazer to show how useless the Krown stuff was, and I repeat, I vidded the application, and it was a waste of time money and follow up sandblasting was required.
  • 26
    Steve Adil Columbia April 14, 2015 at 14:36
    I was surprised that FluidFilm wasn't mentioned. I use it on all of my and my friend's cars. Works great!
  • 27
    Joe NH April 7, 2016 at 14:33
    If you don't see rust buckets on the road, you must live in a desert! Come up to New Hampshire and you'll see more than you want to. Rust and corrosion cost consumers over 23 1/2 billion dollars each year. Automobiles today have much thinner metal panels than ever before and we can debate whether there galvanized or not. One thing there is no debate over is the destructive force of magnesium chloride. This road treatment keeps your roads safe during the winter months, but destroys your vehicle. Today's vehicles will go over 250,000 miles if you change the fluids. Most vehicles rust out before mechanical failure. Rustproofing is worth every penny, and you could spend as little as a couple of hundred dollars a year. Think about it, your second most expensive investment can be protected for less than $200 a year? Here is one company bringing back the rustproofing industry. One dealer at a time... http://nhoilundercoating.com/

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