Is rust proofing necessary?

[codys21]

This may seem like a silly question but I just purchased a used 2015 F83 that spent its entire life in Florida but I live in Iowa. Is rust proofing necessary on today's vehicles, even if this car was bought and driven in Florida?

Thanks,
Cody

[RickFLM4]

I wasn’t aware this was still a thing (as opposed to when I was a kid in the 1970s). I’d say unnecessary now, particularly with aluminum and CF components, but then again I live in FL.

[speedracerM4]

If you're driving during the winter on salted roads and worried about corrosion, look into fluid film.

[quikM2]

I would say no. I have never seen or heard of a newer gen BMW nevermind an M car with rust. I'm sure it exists in some random perfect scenario one in a million one off...

[FlyingLow78]

I think a dealership service department could best answer this question, but speak to a technician and not the service writer. Service writers will try to sell you a service, whereas (hopefully) a technician would just tell you what they've seen on cars in your area. If cars in Iowa are prone to rust, then rest-proofing is probably a good idea.

I have a 2004 E46 that spent most of its life running back and forth between Spangdahlem and Ramstein, Germany every day. It has rust bubbles on the edges of the fenders and tailgate, and the underneath has a substantial salted-road patina. The rust was bad enough that I replaced the rear brake hardlines in their entirety.

[///MB ///M3]

I couldn't help but think of Fargo and the sleazy car salesman...

[codys21]

Thanks for all the replies. I hadn't actually thought about rust proofing until my dad mentioned it because the car lived its life in Florida so the initial dealer may not have tried to upsell any sort of rust proofing, undercoating, etc.

But I didn't really think it was necessary nowadays, either, and I know BMW has the 12 year corrosion warranty so I figure I'd be okay.

[Poiseuille]

in order to answer properly i'll have to admit that in my yute, i myself was (gasp) a car salesman and because of that i can assure you that "undercoating" is and always has been a scam...so much so that the very word "undercoat" is now a euphemism for any fraudulent business activity.
if you keep a car treated with that gunk long enough you'll likely discover that it tends to do the exact opposite of it's advertised purpose: it will trap water (and the brine dissolved in it) within and between unibody panels and produce the inevitable result.
in a personal example, i'm currently looking for a MT E46M3 and the presence of undercoating would be an absolute deal breaker.

[Humdizzle]

rust isn't really a thing anymore. BMW has a 12 year anti corrosion warranty. although the terms of that are vague. I think the rust has to go through the entire panel or something or something.

anyway... the bigger deal is driving on salted roads and having that crap flung up at your bumper, carbon lip, or your own car kicking it up onto the rear bumper.

you can look up which states salt their roads. check the carfax and see where the car has been for a majority of its mileage. personally i dont buy used cars from the northeast or midwest for this reason.

[IB M]

Best way to rustproof your M3 if you live in Iowa is drive a beater in the winter.

[Pvt_D]

In Iowa, there is usually more salt on the roads than snow - it is sometimes downright silly now much brine they use on the roads.
I don't think you need to worry about rust with an M car body/chassis but I've seen rust on the exhaust, you will def see it there unless you keep it very clean after salt events.

What you will need is winter tires.
1, the summer compound on your stock tires will not withstand the brine/salt and will go bad very fast. These tires don't really make it much past 20k miles anyway. Esp the rears.
2. The summers have very little traction under 40' F with that compound, even at 10.5 in. You will find that the 9.5 in wide winter tires have great rain/snow grip but the rears break loose almost anywhere so the rears only last one or two seasons if you drive like I do. You can very well melt those winters off with traction disabled and, after all the brine, make a really cool smoke show.

[65fastback]

Originally Posted by IB M

Best way to rustproof your M3 if you live in Iowa is drive a beater in the winter.

Life is to short to drive a beater...move to the south and drive a M year round on summer tires.