Some controversy arises surrounding whether the procedure works, or
whether it's snake oil. There is no question a cathode anode prevents
rust on enormous bridges, buildings, and ships. But some suggest the
process can't work in a car, either because a) the tires prevent the car
from being grounded; b) the anode hooked up to the car battery is too
weak; or c) both or some combination.
On the other hand seems to be the "old-school" rust proofing through a
chemical and/or oil application, such as Krown is an annual application for $100-120, so by comparison, rust
proofing a car every year for 8 years is the same cost as the electronic
protection.
I agree with Tamn
The electronic process is sound and has been around for a century or more, but it only works when the metal to be protected is "COMPLETELY" grounded. IE. the entire surface to be protected has to be under water (salty or dirty water anyway,.. distilled water is an insulator that's why it goes in batteries). That's why it works on buildings, pipelines, bridges and ships.
One guy actually submerged his car in his pool to get it to work. Another guy had rust right where the wire from the unit attached to the car. These devices are a scam and have been shut down by the government in the US many times but they keep coming back to market under a new name (perhaps because it IS based on proven principal). If you read their disclaimer carefully their warranty only covers painted metal ??? Painted metal won't rust so if a stone chip starts rusting, they're not responsible. Don't believe their fancy electronic jargon. You can build one yourself for about $10 dollars in parts.
All new cars come with corrosion warranty usually five years and they never rust for at least a few years anyway so you don't know whether or not it's working for maybe five years. By then the company is gone or they simply just don't pay unless lawyers are involved.
Krown (which I am an outspoken promoter of) took them to task and asked them to provide a workable set of parameters to test their electronic product because it failed all of their tests. They refused.
I don't think too much of the one time application stuff either and it's not recommended by the APA either. A heavy plastic or rubber coating on every thing works for a while but eventually rust will start somewhere and creep underneath the coating and draw in water with it and keeps it there. It's hard to see as well because it's covered up.
I spent two days under my car scrapping crap off last summer and it was worse because of the rubberized spray. You could see the rust bubbling through but it went inches past the spot and came off wet. I don't think it's a bad idea I just think you need to spray it as well. It may be a waste of money though because you should spray it every year anyway. At about $700 dollars for a new car option, I think you'd be better off going to Krown every year.
I don't care if Krown has to drill holes in my car, it's the only way to get it in there where it really counts. The really bad rust starts on the inside like in the pillars, inside the doors, up under the hood's leading edge and for our cars specifically (protege5) the badges on the tailgate and of course the rear wheel wells (I've caked mine with grease). With this kind of rust you don't see it till it bubbles through the paint from the back and when you go to scrape it off your whole hand is likely to go through.
Krown also has locked in pricing which means the price you pay for the first visit is the price you pay for every subsequent visit provided you go every year. The warranty is even transferable to the new owner if you sell the car which happened for my mom when she bought a used car. If you take a new car in to them (within a year old I think) they will warranty the car forever (even if you sell the car) so that can really help in selling a used car. I have heard of people making claims for rust through and Krown did pay for repairs (although you may have to be persistent).
The spray is also good for electronics and moving parts, if your power windows are well lubricated, them are less likely to fail.
I go every year and pay $125 including tax (but the price has gone up $10 since I locked in). They spend at least 45 minutes spraying my car and let me watch and get them to drill extra holes and spray even more. I went to a cheaper place years ago and they were done in less than ten minutes. No holes no body panels,... not worth the $45.
I go in the spring because it's warmer out giving the oil a better chance to creep (special stuff by the way,... engine oil eats rubber and some plastics) and the shop isn't very busy at that time of year so they are more inclined to take their time. At this time of year they're lined up out the door. But if my car had never been sprayed I would get in that line.
Mazda's are apparently more prone to rust, especially our P5's, they were all completely built in Japan and they use huge amounts of recycled metal over there. I guess it's hard to get all the impurities out in the recycling process. To be honest I never would have bought this car. I just thought rust was normal. I've had three Mazda's that all rusted out well before they died (gas tanks, brake lines, body panels). Then I looked under my sisters Honda civic that was a year older with 100,000 more km on it and it looked brand new compared to mine that was eight years old when I bought it and it had never been undercoated.
I'm glad I didn't check my sisters car before buying because I love my car and I think I'm on top of the rust.