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Rust proofing

5505 Views 5 Replies 4 Participants Last post by  zymmee
Is there any need to rust proof E9x's? I intend to keep my car a long time. If I do not opt for those rust proofing places to drill holes and such is it ok at least to get the undercarriage sprayed?
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This must be an uniquely Canadian topic.

I used to spray all of my cars with oil each year and the process works however our BMW came already coated with Cosmoline which is a waxy material and I didn't want the oil to dissolve it away. Areas where there is lots of salt and sand being sprayed can be touched up with spray cans of Cosmoline or a product called HoneyGoo. Both leave a waxy residue. Acklands is a source for Cosmoline.

My plan is to start oil spraying after the car is 10 years old and until then just keep it clean and touched up where needed. I power wash the under carriage each spring.
I don't know about Canada, but in the U.S. the cars come with a 12 year corrosion warranty. The worst thing you could do is to start drilling holes in body panels - nothing like breaking the seal that is in place from the factory. As far as protective measures, you could periodically (1x/week in the winter) spray the underside of your car with water to wash off accumulated road salt. At the end of each winter season, have the underside inspected to be sure no road hazard(s) opened up the sealing compound from the factory.
It is my understanding the 12 year warranty from BMW requires that you take the car in annually for an inspection and reapplication as required. I agree that washing the undercarriage is important but before I get to 12 years and BMW is off the hook I'll start spraying it myself at the 10 year mark.

That's my plan for our 328 XiT daily driver that sits outdoors all year.

If you really want to save the car from rust, don't drive it in the winter and park it in a dry garage. We have a 15 year old sports car that is not winter driven and it has no rust at all. All that you need is an other vehicle which is your inexpensive winter beater. In fact, this might be more practical and cheaper than annual rust proofing.
I can't check the owners manual on the E93 as it had to be surrendered when the car was repurchased. When the 335d arrives, I will check it to be sure, but my recollection was that there was no requirement for annual inspections to keep the 12 year corrosion warranty in effect in the U.S. I also have an R53 MINI with the 12 year corrosion warranty, and I did check that Owners Manual and Warranty books, and there is no requirement for annual inspections.

It may be that the annual inspection requirement is a Canada thing (as in more severe winters)?:dunno:
It is my understanding the 12 year warranty from BMW requires that you take the car in annually for an inspection and reapplication as required. I agree that washing the undercarriage is important but before I get to 12 years and BMW is off the hook I'll start spraying it myself at the 10 year mark.

That's my plan for our 328 XiT daily driver that sits outdoors all year.

If you really want to save the car from rust, don't drive it in the winter and park it in a dry garage. We have a 15 year old sports car that is not winter driven and it has no rust at all. All that you need is an other vehicle which is your inexpensive winter beater. In fact, this might be more practical and cheaper than annual rust proofing.
Rust to us and the manufacturer are two different things. The manufactured sees it as a hole rusted through the body not the little surface bubble of paint that you or I notice as out car ages.

Totaly agree with R1200 in taking the car off the road for the winter. In an ideal situation. I keep my winter beater on the road and just rent a friends underground condo parking space and switch out cars as needed.
I save on winter tires and rims
Keep the miles down so in fact extend the warranty.
Have a beater when running dirty errands (such as lumber store or driving animals)

But I need to pay for the extra parking spot, insurance and wear and tear on an extra vehicle.
and most of all.... drive a cheep ass winter beater for 5 months of the year.

This being said I still am a 100% believer in oil spraying my car and protecting it under a cover.
In the spring I will wash everything and there will be no rust.

Cosmoline is an excellent product but you can't expect any product to withstand the abuse of the canadian climate.

I just get two cans of rust oil from the auto body section from Canadian Tire and spray'er down. underneath the entire car except for the exhaust and everywhere else where body panels meet or there is a gap.

So for $20 bucks and a messy couple hours I get some piece of mind.
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