Resurrecting an Icon | BMW E90 M3

I predict the BMW E90 generation of M3 will be the next ‘big thing’.

Perhaps not an earth shattering prediction, more a matter of inevitable progression.

We forget that the legendary E46 M3 is now 26 years old and getting a bit long in the tooth for today’s Yeezy wearing enthusiast. By merit of sucession, it falls on BMW’s V8 powered M3 to carry the torch.

With that being said, even the E90 generation is now 15 years old, and well into the crocodile infested waters of planned obsolescence.

So when our good friend Ben said he was in the market for an E90 M3 saloon, we set about finding a car with plenty of ‘the right stuff’.

This late 2010 M3 came with a mere 39k on the dials, full service history and whilst not perfect, provided a great starting point.

A look under the car reveals just how stingy manufacturers are getting when applying protective product to the underside.

As with all of our underbody repairs, we start by removing all the plastic under trays, heat-shields, wheel arch liners, side skirts and exhaust.

The back box on this exhaust had already had some surgery, we suspect to remove the baffles for a more lairy sound.

Cleaning the shell of dirt and contaminants is a key part of any restoration we carry out. Not only does it make working on the car easier and more enjoyable for the mechanic, it gives a much clearer picture of which areas of the underside need closer inspection and repair.

With the underside thoroughly cleaned, Ray could now drop the rear subframe, suspension and fuel tank.

With this M3 only being driven a few times a year, we didn’t need to go as far as stripping down the subframe for powder coating as we do on some of the more comprehensive restorations. All the components were in fine fettle and would not need any attention for some years to come.

You can see just how little protection the bodyshell has when it leaves the factory. Only light primer, bare seam-sealer and a thin beige paint product keeps the elements at bay.

The hard to reach areas beneath the rear subframe and fuel tank have started to develop areas of crusty metal and corrosion that will all need to be taken back to bare metal and chemically treated.

The bare metal areas turn black once the rust converter has gone off and is safe for new primer and product to go back on.

Our aim with projects like this is to replicate the factory finish, with added protection. Rather than paint over the entire underside in base coat, Ray carefully repairs the isolated areas of corrosion, applying fresh seam sealer and carefully painting in detailed areas to create an invisible repair.

Once happy with the paint work, Ray covers the entire underside and subframe assembly in a thick layer of clear cavity wax, maintaining a factory look whilst fully protecting the car.

We much prefer to use a clear wax instead of some of the alternatives that coat everything in a black sticky product, it makes working on the car unpleasant and historically has been used to hide corrosion and poor quality repairs.

Buyers beware.

With the future-proofing now complete on this E90 M3 body shell we can start putting the fuel tank and rear subframe back in and making it ready to roll again.

During the strip down stage we identified that a number of the heat shields had corroded mounting points and were best being replaced before reassembly.

With the car looking better than factory fresh, there’s only one thing left to do. Photoshoot, of course!

I hope this article sheds some light on how important it is to catch corrosion early, especially on cars that we consider relatively new. Speaking to industry insiders, we are aware just how the 10 year built in obsolescence comes first and foremost at the expense of the bodyshell’s integrity.

The process shown here is typical of the level of repair we would carry out on most well looked after premium cars of this age, and we are seeing more and more E92 and Porsche 997’s coming through the workshop that show this level of corrosion (and worse). Getting on top of it sooner rather than later is always cheaper in the long run and will make long term ownership of that car a far more enjoyable experience and when it comes time to sell, ensure that your example is one of the best on the market.

– Callum

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