BMW E46 M3 Rear Wheel Arches Rusting
The 2nd most common E46 enquiry we receive (after RACP work) is 'Rear Arch Rust'.
Arch rolling on an E46 is horrendous. E46 NFS GTR Wide Arch Bodykit To Fit Coupe And Cabrio Only This kit will fit the saloon and touring but rear arches foul the door so modification will be needed Inspired By The E46 GTR Featured In The Popular Need For Speed Video Game Consists Of Wide Front Bumper And 4 Bolt/Rivet On Arch Extensions Designed To Work With The Original BMW Sideskirts and Rear Bumper Adds 50mm a side at the front and 90mm. F/Bumper Reinforcement. X Member /Mount Panel. R/Bumper Reinforcement. 4 pages 1 2 3. BMW 3 SERIES E46 SALOON/ESTATE BONNET 1998-2001 £186.85 Buy. The 2nd most common E46 enquiry we receive (after RACP work) is 'Rear Arch Rust'. All E46 Rear Arch corrosion starts from the Inner Arch area. Regardless if you can only see a small blister on the Outside Arch area. We can guarantee you that the epicentre is hidden under Seam Sealer on the Inner Arch area.
All E46 Rear Arch corrosion starts from the Inner Arch area.
Regardless if you can only see a small blister on the Outside Arch area.
We can guarantee you that the epicentre is hidden under Seam Sealer on the Inner Arch area.
This means if you aren't tackling the Inner Arch area then the corrosion will return.
We've been tackling E46 Rear Arch corrosion for many years now and if you've followed us on our YouTube channel, and Facebook/Instagram pages you would have seen several of our repairs.
Redish offer 2x different E46 Rear Inner Wheel Arch Repairs:
- New BMW Metal Inner Wheel Arch Panels £2895.
or - 3M Panel Bond Adhesive (aka CSL style) Inner Wheel Arches £1595.
(Prices are for both sides, and include all paints/materials/labour, and VAT).
By far the most popular version is our 3M Panel Bond Adhesive (aka CSL style) modification.
This is where we remove a section of the Inner Wheel Arch Panel - especially the 'U shape channel' which removes 99% of E46 Inner Arch rust.
We leave this cut as that's how it is on the CSL Wheel Arches.
Once all the remaining loose corrosion has been removed/cleaned from the Outer Wheel Arch 'U shape channel' we treat any bare metal with a chemical to stop it further corroding.
We then improve tyre-to-arch clearance by gently closing some of the Outer Wheel Arch 'U shape channel' (all hidden on the inside of the arch system).
Then the area is thoroughly dried and inspected before we protect it with Etch Primer.
Then we carry out our pioneering-repair to bond the Inner and Outer Wheel Arch Panels together using 3M Panel Bond Adhesive - just like a CSL.
We also ensure the remaining Outer Wheel Arch 'U shape channel' is not only completely filled with continually-joined 3M Panel Bond Adhesive, but also envelopes the entire front face of the 'U shape channel'.
This means the vehicle retains it's strength of the 'U shaped channel' but it's completely flat and therefore water/salt/mud cannot collect and instead simply slide down the newly created vertical line and fall onto the ground.
Once cured we further protect the repaired area (Inner Arch area) with High Build Primer, Sprayable Seam Sealer (textured), and 'Redish E-coat' OEM colour.
Finally we treat the internal hidden sections to copious amounts of high performance Cavity Wax for total protection.
Once cured our repair is rock-solid, and will not allow corrosion to form.
This is a repair which Redish Motorsport have pioneered after years of experience with the E46 chassis and especially chasing corrosion, as well as having utter confidence to open up BMW chassis's to component metal form and produce adequate solutions to common problems.
We are soon-to-release a brand new video detailing our 'Rear Arch modification aka CSL style'
In the mean time please feel free to watch our old way of the repair using New BMW Metal Arch Panels:
Why you’d want a BMW E46 M3
A decade after the Golf GTI had turned the sports car concept on its head and shown that a hot hatch could be as chuckable as a roadster, BMW brought out the M3 in 1986.
This homologation special was only meant to help the company win Touring Car races, but it started a whole new genre and added excitement to the BMW range that it couldn’t do without. The E36 M3 of ’93 was accused of being more of a marketing tool – a tad unwieldy and overweight – but the E46 was designed to address that.
Priced on a par with the Porsche Boxster S, the E46 M3 was streets ahead in performance, challenging the much pricier 911 and Audi RS4. Stiffened, wider-tracked with big wheelarches and a massive front spoiler, it packed a 3.2-litre straight-six substantially re-engineered by the M division to generate 343bhp at 7900rpm and 269lb ft at 4900rpm. A six-speed Getrag gearbox took power to the rear wheels via a variable-lock limited-slip diff, developed with GKN.
Modern technology meant that ABS, switchable Dynamic Stability Control, Cornering Brake Control and Traction Control systems were standard. It sounded brilliant, too. ‘The grunty rumble from the quad exhausts at idle gives way to a serrated wail as the straight-six climbs to its redline,’ enthused Autocar.
Aluminium was widely used to keep weight down, for the bonnet and brake calipers as well as suspension components, though the car still ended up heavier than its predecessor thanks to a high level of standard equipment inside the opulent leather-clad interior.
As a package, it was a triumph – the original M3 grown up. If you could criticise anything, it was that there wasn’t a lot of power below 2000rpm. But because it was then seamless up to 8000rpm and you had six gears to play with, it was hardly a big problem.
All cars were officially limited to 155mph, although Autocar’s test model happily topped 160mph and a limiter-delete was optional on the CSL version, allegedly allowing a 170mph top speed.
Coupés now command a price premium of c10% over Convertibles, but while manual gearboxes are preferred over SMG, condition and history are far more important.
There is a huge premium to pay if you want a CSL, however; the CS is currently a good option, with prices about 20% above the standard model. Crucial checkpoints are the rear axle carrier panel cracking, VANOS faults and head-gasket failure.
Images: Tony Baker
Subframe
Rear axle carrier panel is E46’s weak point: the structure cracks from stress loading and proper repair is complex. Check if it’s been done, and done well.
Engine
The engine is highly stressed and can suffer from a number of issues, especially if not scrupulously maintained. Rattling from the VANOS variable cam timing needs urgent overhaul. Head-gasket failure can manifest through misfire or pinking (budget c£1500 to have it done). Conrod bearing weakness should have been cured on an early recall.
Suspension
Forged-aluminium lower wisbones are unique to M3; ditto bearings and bushes. They lead a hard life so look for wear.
Wheels
18in alloys were standard; 19in optional (standard on CSL). Diamond-cut rims are costly to refurbish. Brakes are more than adequate for road; upgradable for track.
Gearbox
Six-speed manual gearbox is strong, but the optional SMG clutchless sequential shift can suffer slow changes and even apparent loss of fourth as pump wears.
Interior
Look for wear on driver’s outer bolster, which a good trimmer can refurbish or replace; Nappa leather can crack if it gets too dry. CSL interior is all different.
Electrics
Damp, especially on cars kept outside, can wreak havoc with electrics, as moist air condenses inside. Inspect the history, and confirm that everything works.
Hood
Folding top should fit well: check carpets for damp, hood for damage and test operation; most parts can be sourced on eBay. New Sonnenland hood is c£1000.
All versions are rapid, great-handling cars but time and neglect bring problems. The complex BMW/Siemens MSS54 engine-management system seems trouble-free, but the VANOS variable cam timing suffers with age. If it’s rattling, budget for a rapid service: it may be hardened seals but could be loose bolts or stripped splines that can wreck the motor.
A lack of power (relative to what it should be!) also indicates the need for an overhaul. A diagnostic test will confirm. A misfire, or pinking when accelerating gently uphill at 2000rpm, may be a symptom of head-gasket failure, fairly common at 80-100k miles.
The SMG gearchange can give trouble due to pump wear. A rebuilt pump is close to £1000 exchange, but a new BMW item is more than twice the price. Servicing is not cheap: even at independents, an Inspection 1 will cost £500-plus; and an Inspection 2 £650-plus.
Modifications are common, so check what’s been done and if the car has been abused on track. ECU upgrades, engine tuning, blueprinting, suspension and chassis upgrades, brake upgrades including AP Racing kits, different wheels and body mods are among the options.
The rear suspension incorporates M3-only links with steel balljoints: this stiff set-up plus the massive power put far greater stresses through the E46 shell than it had been designed to take and it cracks. Inspection and the involved repair is best carried out by an experienced specialist.
BMW E46 M3 price guide
M3
- Show: £20,000*
- Average: £10,000*
- Restoration: £5000*
CSL
- Show: £75,000*
- Average: £45,000*
- Restoration: £25,000*
*Prices correct at date of original publication
BMW E46 M3 history
2000 Mar E46 M3 launched
2002 Sep build starts
2001 Feb Right-hand-drive M3 on sale; Mar/Apr Convertible added, heavier so 0-60mph 5.1 secs; autumn, GTR racer announced for American Le Mans Series, with 460bhp 3997cc V8: it won!
2002 Feb M3 GTR on sale: 380bhp dry-sump alloy V8, carbonfibre roof, spoilers, rear wing; 10 made, three ‘sold’ for €250,000 but later returned to BMW. SMG II: 11 modes and ‘launch control’
2003 May M3 CSL added: 110kg lighter (carbonfibre/GRP and thinner glass used), 360bhp, faster semi-auto gearchange, bigger brakes, sharper steering and suspension; c1395 made, code BL95 LHD, BL96 RHD
2004 M3 Silverstone (cosmetic special) offered in the UK market only; 50 built
2005 M3 Coupé Sport (CS/ZCP) pack offered for base model: CSL wheels, steering and suspension
2006 May Coupé production ends
2006 Aug Soft-top production ends
“I’ve always had petrol in my DNA,” comments Peter Brewin, having sold his TR6 and M635CSi to buy this M3 eleven years ago. “I’d had them both for 10-12 years and wanted one car that combined the best of both. Porsches were too small and I like BMW detailing. I wanted one that was spot-on and spent 15 months looking.
“This car had one owner, full BMW history and has averaged 2500 miles a year. It was pampered by a wealthy collector and had all the options. I’ve taken it to the Revival, Le Mans Classic and touring in France.
“I drive it only when I really want to, and the conditions are perfect. Even the wiper blades are original: they never get used! The only repair it’s needed was a diff seal. I’ve fallen in love with it to such an extent that to prise me away from it would be a real challenge!”
AUDI RS4
With a 2.7-litre turbo V6 producing 376bhp, the 4WD 5-door estate RS4 flew. It’s scarce and still reassuringly pricey. Quicker in a straight line than M3, if not as much fun on the twisties.
Sold 2000-’01 • No. built 6030 • Mpg 16-25 • 0-60mph 4.7 secs • Top speed 155mph (limited) • Price new £46,500 (2001) • Price now £18-25,000*
MERCEDES-BENZ CLK55
E46 Rear Arch Corrosion
AMG decided the only way to build a Merc to match the M3 was to sling a 5.5-litre V8 under the bonnet, with a five-speed paddle-shift auto and firmer set-up. Now, it’s quite a bargain.
Sold 2001-’07 • No. built c15,000 • Mpg 16-33 • 0-60mph 5 secs • Top speed 155mph (limited) • Price new £57,000 (Coupé, 2002) • Price now £7-15,000*
*Prices correct at date of original publication
E46 Rear Arch Rolling
The E46 M3 is thoroughly worthy of the name, and enthusiasts have wasted little time in pushing prices into the collector zone – especially for the rare CSL (and the half-way-house CS is beginning to follow).
If you possibly can, buy a car with good, full service history and evidence of having been garaged and cherished. Neglect is extremely costly to rectify.
FOR
E46 M3 Rear Arch Rust
- Great handling and glorious noise
- Fabulous performance
- Usable every day
- Values for best are appreciating
AGAINST
- Rear end cracking: costly to fix
- Some engine issues as they get older
- Many have been modified and/or abused on track, so inspect uprated ones carefully
BMW E46 M3 specifications
- Sold/number built 2000-’06/55,506 Coupé, 29,633 Convertible
- Construction steel monocoque
- Engine iron-block, alloy-head, dohc 24-valve 3245cc ‘six’, with sequential multi-point injection; 343bhp @ 7900rpm-360bhp @ 7900rpm; 269lb ft @ 4900rpm-273lb ft @ 4300rpm
- Transmission Getrag six-speed manual, driving rear wheels; about 50% (including all CSLs) have optional SMG sequential semi-automatic
- Suspension: front MacPherson struts rear multi-link, coil springs; anti-roll bar f/r
- Steering power-assisted rack and pinion, 3.2 turns lock-lock (3 on CSL/CS)
- Brakes ventilated discs, 325mm front, 326mm rear, with servo; CSL/CS 348mm front
- Length 14ft 9in (4492mm)
- Width 6ft 41/2in (1947mm)
- Height 4ft 6in (1372mm)
- Wheelbase 8ft 11in (2725mm)
- Weight 3047-3649 (1385-1655kg)
- 0-60mph 4.5-5.1 secs
- Top speed 155-170mph
- Mpg 15-30
- Price new £37,850/41,400 (Coupé/Convertible, 2001)
READ MORE
Bmw E46 Rear Arch Repair Panel
Malcolm McKay is a regular contributor to Classic & Sports Car