E9x M3 corrosion

[Tony B]

Don't panic - I have not found any (apart from some cosmetic deterioration of under bonnet nuts) but I wonder whether there might be any weak spots hidden away, waiting to spoil my keeper, in a few years?

I guess Canadian owners might be best placed to comment, if any weaknesses do exist the winters there ought to find them out.

So - has anyone had a problem with corrosion vulnerability, so that I can take pre-emptive, protective action on my MY2012 car, which I plan to keep for some time.

Unless I win the lottery and buy a 911 GT3....

[Flying Ace]

never heard or seen such. Further, the car has a unlimited mileage corrosion warranty (as I recall) in the USA

[GRUESOM3]

If u thinking about 50 years from now , start taking it apart and Por-15 everything

[Helmsman]

Originally Posted by Tony B

Don't panic - I have not found any (apart from some cosmetic deterioration of under bonnet nuts) but I wonder whether there might be any weak spots hidden away, waiting to spoil my keeper, in a few years?

I guess Canadian owners might be best placed to comment, if any weaknesses do exist the winters there ought to find them out.

So - has anyone had a problem with corrosion vulnerability, so that I can take pre-emptive, protective action on my MY2012 car, which I plan to keep for some time.

Unless I win the lottery and buy a 911 GT3....

Tony,

been thinking about this myself, why keep working on the outside and not care about the rest, also as DD around year in Sweden. Started to check with work shops doing protection for a living - $700-1k for complete car so not too bad - but never got around to it. Next plan is to do a bit of spraying myself as a starter. At least over here there are various stuff to get, guess our winters and salty roads...

Keep you posted the day it happens.

Cheers

[tdott]

Since the Hood is Aluminium, the front fenders are plastic, the side skirts are plastic.

I'm not sure if the Trunk is aluminium or not, but if not, the trunk, doors, rear quarters as well as under the side skirts are going to be the most likely places for rust.

Roofs on sunroof cars also, CF roofs won't rust obviously.

[Helmsman]

Certainly the outside will stay fresh, Im refering to the underneath of the car were corrision for sure is going here and there.

Cheers

[oolas3]

Try this stuff: http://www.amazon.com/Bio-Kleen-M018.../dp/B00FDWBRBQ

[apecush]

Rear steel subframe and suspension bits show some surface corrosion. If your rear wheel arches are chipped from road debris, this may cause some issues in the future, however, in general, the rear end is designed rather well with respect to collecting sand and salt. If you live In a rather corrosive environment (which I do) every spring, jack the car up, remove the wheels, and fender liners, and pressure wash the underside of the car.

[Tony B]

Originally Posted by Flying Ace

never heard or seen such. Further, the car has a unlimited mileage corrosion warranty (as I recall) in the USA

We (in the UK) have a 12 year warranty (not sure of mileage limitation, if any) which sounds quite good, but only covers corrosion from inside out, so stone chipping of vulnerable areas, which leads to corrosion from the outside, is not covered.

I used to religiously clean the wheelarches of my Sierra Cosworth, after removing the plactic inner liners, before and after each winter. Even with the liners in place, seemingly providing plenty of protection, the amount of crud that built up around the arch lips was quite surprising. And that was with a very low mileage car, hardly ever driven in wet/dirty conditions.

Granted that a 2012 BMW is going to much better protected than a 1980s Ford, but having grown up with disintegrating Alfas and Lancias I do tend to be a bit sensitive about this.

The underside of the E9x body is largely covered by (non-metal) panels to minimise air turbulence, so that is probably good news, but if I can't see it....

Must stop worrying....glass is half full, not half empty.

[Will f]

I too am from the UK and have experienced corrosion to the Shadowline trim (the black strip that goes around the front and rear windows on both sides) not covered under the 12 year ant-corrosion warranty either!!

[New_m3]

The rear steel subframe is starting to rust on mine - there's already a few small holes. I was told it wasn't covered under the 12 year rust warranty as unpainted surfaces only come with a 3 year warranty.

[Helmsman]

There you go mate, these are the bits I had in mind doing some protection on. And now you provided further stimulation...!

[Killerfish2012]

Originally Posted by Tony B

Don't panic - I have not found any (apart from some cosmetic deterioration of under bonnet nuts) but I wonder whether there might be any weak spots hidden away, waiting to spoil my keeper, in a few years?

I guess Canadian owners might be best placed to comment, if any weaknesses do exist the winters there ought to find them out.

So - has anyone had a problem with corrosion vulnerability, so that I can take pre-emptive, protective action on my MY2012 car, which I plan to keep for some time.

Unless I win the lottery and buy a 911 GT3....

A few months ago, my oem springs broke. After replacing them with low mileage oems, I noticed that the springs had a thing coating of plastic/rubber, and once that was gone, several spots or rust showed up. The spring broke right across one of these spots. I just had rustblock professionally applied to my car last week after seeing what the slow corrosion was doing underneath recently. If you live in an area where road salt is used during the winters, you're advised to get some rustblock. Compared to my 335I, the M3 metal corrosion resistance leaves much to be desired.

[krzykk]

Originally Posted by Tony B

...

I used to religiously clean the wheelarches of my Sierra Cosworth, after removing the plactic inner liners, before and after each winter. Even with the liners in place, seemingly providing plenty of protection, the amount of crud that built up around the arch lips was quite surprising...

I haven't done that on my Sierra Cosworth and remember having issues with rust.

[bimdo]

something that would probably help to prevent corrosion is to make sure the underhood drains aren't clogged.there are two,one at each corner,towards the windshield if you pop the hood and look in from the front.they are recessed down a bit.each is covered with a plastic mesh basket about 3"x6" which has little finger notches to allow you to pull it out and dump.my car is garaged at home and not parked outside much,but still has leaves in that drain when i check it.

does anyone know exactly what these drain?

[Beemdog]

Those mesh baskets catch the leaves before they get into your cabin filter intake tract. That inlet feeds fresh air to the car interior.

[crypticc]

Originally Posted by Beemdog

Those mesh baskets catch the leaves before they get into your cabin filter intake tract. That inlet feeds fresh air to the car interior.

Thought they were just water drains?

[radiofrequency]

It might be a good idea to cryo-detail the underside of the car prior to application of a corrosion prevention product. At least then you are not placing a coating over existing corrosion. Take a look over here: http://www.pedrosgarage.com/Site_5/F...ad_Grime!.html

[Tony B]

Following up on my original question regarding underbody corrosion.

Take a look at the video below, created by Redish Motorsport, BMW M specialists in Bristol UK. Redish have been doing fantastic underside restorations on E46 M3s for years, including reinforcement plates to cure the floor cracking problems, which are a result of too thin steel, poor quality welding and bad design (putting spot welds in high stress areas).

Their attention to detail is becoming legendary.

I had already contacted them about getting the rear sub-frame restored on my car (at 38k miles the sub-frame is covered in significant and unsightly surface corrosion) and powder coated, and they said they were about to do a sub-frame removal job with another customer's car, for the first time, to facilitate underbody refresh.

The video makes very depressing viewing. It starts reasonably well, but gradually gets worse and worse, as they examine the underbody surface in detail. The rust is all over the place, in the sub-frame area, and at the bottom trailing edge of both cills, around the boot floor aperture, inside the fuel filler tube, and and and.....

It looks like BMW now either use very poor quality steel, or their pre-paint preparation is very poor, as this car (2011, and 100k miles, but obviously very well cared for) has rust growing all over the underfloor panel adjacent to the rear subframe and everywhere that has not been protected with seam sealer.

And this rust is growing underneath the electro-coat and the painted surface, so not caused by stone chippings on the surface.

I am pretty shocked at the lack of protection. BMW are getting away with it, because the multitude of under-floor plastic panels, cill covers etc, hide the actual problem.

A 12 year anti-corrosion warranty with more get outs than I can shake a stick at, is not going to provide me with much comfort.

I had intended to keep my E92 M3 indefinitely, but this is making me think again. Probably £2.5 to £4k to have the Redish job done, and doing it will almost certainly give BMW another reason to avoid paying against any corrosion claims in future, on any part of the car.

[drrust]

The white corrosion product is the reaction of the zinc coating used on the steel. This is typically referred to as white rust. The spot welds tended to show red rust as the zinc either evaporated or alloys with the steel substrate.

Typically cars will rust through at hem flanges. This usually is from the inside out. It was interesting to see that they reapplied a wax inside all of the box sections.

Remember, modern vehicles are designed with with about a ten year rust through warranty. The surface corrosion seen likely wouldn't have progressed far enough for a warranty claim. Also at some point they want you to have to buy a new car!

[Scrippy]

Originally Posted by bimdo

something that would probably help to prevent corrosion is to make sure the underhood drains aren't clogged.there are two,one at each corner,towards the windshield if you pop the hood and look in from the front.they are recessed down a bit.each is covered with a plastic mesh basket about 3"x6" which has little finger notches to allow you to pull it out and dump.my car is garaged at home and not parked outside much,but still has leaves in that drain when i check it.

does anyone know exactly what these drain?

Air down and out.

[Scrippy]

Originally Posted by Tony B

Following up on my original question regarding underbody corrosion.

Take a look at the video below, created by Redish Motorsport, BMW M specialists in Bristol UK. Redish have been doing fantastic underside restorations on E46 M3s for years, including reinforcement plates to cure the floor cracking problems, which are a result of too thin steel, poor quality welding and bad design (putting spot welds in high stress areas).

Their attention to detail is becoming legendary.

I had already contacted them about getting the rear sub-frame restored on my car (at 38k miles the sub-frame is covered in significant and unsightly surface corrosion) and powder coated, and they said they were about to do a sub-frame removal job with another customer's car, for the first time, to facilitate underbody refresh.

The video makes very depressing viewing. It starts reasonably well, but gradually gets worse and worse, as they examine the underbody surface in detail. The rust is all over the place, in the sub-frame area, and at the bottom trailing edge of both cills, around the boot floor aperture, inside the fuel filler tube, and and and.....

It looks like BMW now either use very poor quality steel, or their pre-paint preparation is very poor, as this car (2011, and 100k miles, but obviously very well cared for) has rust growing all over the underfloor panel adjacent to the rear subframe and everywhere that has not been protected with seam sealer.

And this rust is growing underneath the electro-coat and the painted surface, so not caused by stone chippings on the surface.

I am pretty shocked at the lack of protection. BMW are getting away with it, because the multitude of under-floor plastic panels, cill covers etc, hide the actual problem.

A 12 year anti-corrosion warranty with more get outs than I can shake a stick at, is not going to provide me with much comfort.

I had intended to keep my E92 M3 indefinitely, but this is making me think again. Probably £2.5 to £4k to have the Redish job done, and doing it will almost certainly give BMW another reason to avoid paying against any corrosion claims in future, on any part of the car.

I've watched posted videos by these guys and it is truly car-pornography. The results look awesome!