People say the way car manufacturers dip the cars now before painting, it's really not necessary to add layers on top of layers. It's a thing of the past. That's why all the manufacturers have extended rust warranties now.
http://www.cartalk.com/content/columns/Archive/1996/September/10.html
Dear Tom and Ray:
I'm an old geezer who last bought a new car in 1978. Obviously, the manufacture and the warranties are different on my new 1996 Buick LeSabre. Living in the rust belt, I can't imagine NOT undercoating the underside of the car. The salesman says no, that it might void my warranty. And besides, he says the car is made so well that it doesn't need additional undercoating. Am I living in the past, or is the Buick Division bamboozling us? -- Robert
Tom: First of all, Robert, the last time we used the phrase "geezer" in one of our columns, some nice, older gentleman wrote to us and really let fly. So we want to make it clear that you're the one who used the term "geezer," not us, OK?
Ray: Now, for all the rest of you geezers out there (including my brother, by the way) here's the answer: The dealer is right.
Tom: I assume you're talking about "rustproofing," Robert, the modern-day equivalent of undercoating. The problem is that a poor job of rustproofing (and we've discovered that most rustproofing jobs are poorly done) can actually encourage rusting! By plugging up drain holes in the undercarriage, the rustproofing can prevent water from draining, and actually make the underbody rust faster. So we recommend against it these days.
Ray: Plus, cars are better made these days. It's not that they won't rust, it's just that they seem to be taking longer to rust.
Tom: So given the downside of the sloppy rustproofing process, and less of a necessity for additional rust protection these days, I'd recommend you skip the rustproofing, Robert. And use your senior-citizen discount at the car wash a little more often instead.
http://www.cartalk.com/content/columns/Archive/2004/June/06.html
Dear Tom and Ray:
I live up in Vermont, and I just bought a new Toyota Tacoma. Many of the people in my town tell me that they protect their vehicles from winter salt damage by having their undercarriages sprayed with used motor oil. There is a guy who has a business doing just that. Apparently, it's legal up here, and it's not terribly expensive. Do you think it's an effective measure to take, and does it do any harm to the vehicle? -- Roger
TOM: As far as we can tell, Roger, this is an old-fashioned remedy that's been passed down in rusty old places in the great frozen North. And like a lot of old folk remedies, it has its roots in truth.
RAY: But it's been surpassed by more-effective, environmentally friendly solutions.
TOM: In the old days, before metal body parts were "dipped" and rust-proofed at the factory, cars and trucks in the great frozen North used to rust out in no time. It wasn't unusual to see a car with its body rusted through after only five or six years.
RAY: So, soaking the whole underside of the car with used motor oil seemed like a good idea. It does inhibit the rusting process, at least for six months or so. And it was in plentiful supply. Heck, you were going to throw it away anyway, right?
TOM: And did it hurt the car? Well, probably not. You wanted to avoid rubber bushings and stuff that could be degraded by oil. But as long as you closed the doors first, you were usually OK.
RAY: The problems are that, aside from being less necessary nowadays, it's a terrible thing to do to the environment, and you have to do it every year. As you can imagine, in addition to the flood of oil at the application site (unless the guy uses an approved collection system), you drive away dripping the stuff all over the state.
TOM: Given the strict regulations shops face now in disposing of used oil safely, I can't imagine that anyone in charge of environmental regulation or drinking water is going to look kindly on this process. So I'd definitely double-check (or triple-check) the legality of doing this.
RAY: Our recommendation would be to skip the used-motor-oil shower, Roger. If you feel you need more rust protection than the factory provides, I'd ask a mechanic about applying a rust-proofing product designed for that purpose. They cure within hours, provide a much cleaner solution and can be checked and touched up annually, as necessary, without environmental damage
http://www.cartalk.com/content/columns/Archive/2002/March/05.html
Dear Tom and Ray:
I just purchased a 2002 Nissan Maxima GLE and won't be picking the car up for a few days. We were pitched the usual after-sale banter about undercoating, rust protection, etc. But one of the items was new to me, and I wondered what you thought about a Teflon paint-protecting product offered for $250. It's supposed to fill in the paint pores and protect against acid rain. Do you think it has any merit? -- Leo
Tom: No.
Ray: Now that the entire universe has caught on to the fact that rust-proofing, undercoating and pin-striping are all unnecessary, dealers have had to be creative and come up with new ways to get back some of the money they've bargained away in the sales process.
Tom: At most dealerships, there's a whole department dedicated to getting you to spend more money AFTER you've already agreed on the purchase price of the car. They make money on financing, extended warranties, door protectors, security systems and Tibetan incantations. Not all of that stuff is bogus, but some of it is clearly unnecessary.
Ray: I actually don't know anything about this specific product, but I know that car finishes are pretty darned good these days, and with a reasonable amount of care (or even without, in most cases), the finish will last longer than the car. So if you're picky about the way your car looks, I'd buy an $11 can of Zymol wax and leave the Teflon for your pots and pans, Leo.
