can anyone tell me if the factory warranty voids if i take my brand new mazda3 to a third party like Krown or Ziebart?

 

I don't know what Krown is, but the rust-through portion of your warranty will be voided if you have it rust-proofed at Ziebart. FWIW, if you're looking at rust-proofing, don't, the process does more damage to your car than good and it will most likely rust through faster than if you just left it alone.

 

I agree.
In the '80's when I was in the business, we worked on older Volvo's and BMW's at one shop I worked at. One of the Volvo models most common to our shop was the 122, or Amazon, known rust buckets. The nicest one I had ever seen, with almost no rust had never been undercoated or rust proofed. An even coat of surface rust on the chassis only... and IIRC, it was a 1964 model, already 20 some yrs old at the time.

 

thanks sihpo & virgin1. so you're saying even the in-house rust proofing that they claim to last a lifetime is just as worthless?

 

I don't know what they're using these days, but in the past what you were really paying for was a warranty that usually ran out before you actually needed it. Some that required you to pay for part of it, or did not provide a rental car while yours is being repaired.
But once rust through starts, that's the beginning of the end anyway. Trying to keep up with it is nearly impossible in the long run, short of a complete disassembly/body work/rebuild.
I've seen waxed based sealants, oil based, tar based and plastic types, but they will all eventually fail and allow moisture to enter and be held. That's what does the real damage... that and winter road salt. It was a way for dealerships, and independents alike, to make a living, but did little for the customer.
So if you live in an area that gets a lot of snow and ice, and they use road salt, your best bet is to take the car to an automatic car wash that has high pressure sprayers to clean the undercarriage as often as needed... say, twice a month or once a week, depending....
In other words, I would save my money for proper and regular maintenance instead of a once and done fix that offers you a false security.

 

There is no such a thing as "in-house rust proofing", just "in-house customer wallet draining"; save your money, the only rust proofing you will ever need is what was built into your car at the factory.

 

thanks again guys. you're so right about in-house rip off shipo. i saved myself $3,000 for the in house rustproofing. actually when i declined it the manager of the dealership looked at me like i was a 10 yr old punk who didn't know any better. now i know i'm depriving him of precious $$$ which he rips off unwitting clients. when i came to pick up my new car he saw me but did not even bother to congratulate me even for show. i pity the clients he has duped over the years. $3000 can go a very long way. i can't even use it up even if i go for weekly car wash every winter for the next 20 years. thanks virgin1 for that advise.