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E46 Subframe

Discussion in 'E46 (1999-2006)' started by pdecourt104, Dec 12, 2015.

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    pdecourt104

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    I thought I'd introduce myself via a post regarding a tragic, but not unheard-of, failure on my 2000 328Ci. I live in Northern Virginia. I'm new to BMWCCA (as of today), but have owned BMWs since 1980-something. My 2000 328Ci is a low mileage car I bought in early 2013 as a commuter car, so I wouldn't have to drive my Porsche Boxter to work 25 miles one-way. Anyway, I'm retired now, so I just rotate between the Porsche, BMW and a restored 140 Hp Triumph TR6 to drive to the golf courses nearby. They are all great cars to drive, and everything works (except the nav system in the 328).

    My favorite local mechanic who specializes in BMW, Mercedes and Porsche installed new Bilstein Sport rear shocks for me a couple of weeks ago. He called me over to the shop to show me a big problem he'd found. The rear subframe was severely cracked around the rear driver side differential carrier mount and the carrier was hopping all around the place when the car was put in gear. It turns out this is a problem that plagues E46 models, especially M3 track cars. I requested courtesy assistance from BMW North America for repair of the cracked subframe and they agreed to pay for 25% of the repair cost. There was a time they would have payed 100% for the repair under settlement terms of a class action law suit back in the early 2000's, but they are no longer bound by the suit settlement to make full reparation. The catch is the work has to be done through a dealer. The local NoVA dealer actually doesn't do any of the work themselves. They farm it out to a local body shop. The body shop is the best around, I know from personal experience with work they did on the Porsche. The full BMW approved repair should cost about $3000, BUT the dealer charges $4,700. That means basically I would be paying the full repair cost and the dealer would pocket an additional $1,350 from BMWNA. I talked to a BMW exec about this dubious situation, and she said there is nothing BMW can do about dealer pricing.

    So, I elected to take the alternate route and have a qualified race prep shop repair the rear end using Turner Motorsport's kit, and replace coil springs and carrier mounts while they're at it. The kit is intended for reinforcing the rear end of track and street cars before cracking occurs, but is also used for ager the fact repair. While I'll be out-of-pocket almost $4,000, I think I'll be ahead because the alternate repair method is a better engineered approach. You can access archives of the BMW repair methods on-line and compare to the alternate approach using kits like Turner's. Check ou Road Race Technologies, Dulles, VA, web site. There are other kits out there, but Turner's is probably the most often used.

    Anyway, the E46 subframe issue came as a surprise to me. I guess I didn't know the car as well as I thought. The original chassis design leaves a lot to be desired. It's one of the worst design flaws I've ever learned about affecting a BMW. Nevertheless, I've committed to keeping the car in the corral, and treating it like a project, similar to my 40 year old TR6. I haven't done anything with intake or exhaust, and really wouldn't consider more drastic upgrades to the E46 motor. It's really good as it comes from the factory. But, maybe it's time to have a little fun with the car, not that it hasn't been a blast to drive. Due to age (of the car), I have to deal with sagging door seals and that sort of thing. No big deal, and it would look almost new with a little more spit and polish. Only 78,000 miles so it may be the last BMW I'll buy.

    I look forward to reading tech tips and expect the forum will be a great place to get information on projects I might want to do with the car.
    • Member

    dmmai

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    .
    Welcome to the forums.

    A friend here in the Midwest has been driving his 2000 328i for more than 250,000 miles and still enjoys it.
    Since the sub-frame issue was corrected (Turner kit) his car has been largely trouble free.
    Enjoy
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    • Technical Service Advisor

    charlson89

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    Welcome sorry to hear about that issue I had it on my 330i but thankfully the crack was small enough to do the resign repair.
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    ramitchell

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    I too heard about the sub-frame after I bought my E46 (2002 330CiC 55k miles). I replaced the rear shocks last year with yellow sport Koni's and did not see anything out of the ordinary. Are these cracks very visible and are there any signs such as noises, odd braking/handling to indicate a crack?
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    • Technical Service Advisor

    charlson89

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    They are not easy to see if they are then it's to late to do the simple repair. You will need to drop the subframe slightly and look at where it attaches for any cracking in the body.
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    MGarrison

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    I'm hardly an expert on it, but I have to guess that by the time you hear something, it's past the point of cheap repair.

    Should be lots of pictures out there - google, bimmerforums, etc.

    There are some pics in the gallery link on the Turner kit page - the last one shows that with the subframe installed, only a small vertical crack would be showing (in that instance), but the damage hidden from view is worse.

    http://www.turnermotorsport.com/p-91-e46-rear-chassissubframe-reinforcement-kit.aspx
    • Member

    ramitchell

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    Thanks for the advice! I read where BMW was offering a free inspection at one time for this and I believe that has expired. I'm going to check with my local BMW dealer to see if my E46 was ever serviced or inspected for this.

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