Like most FR cars, the rear subframe bolts to the chassis via four mounting points. The entire rear suspension, rear brakes, and arms all attach to the rear subframe as well. The subframe is just the tubular frame that cradles the rear differential. So when people say that the subframe is cracked or reinforced they are inaccurate. Literally, every one of my friends with an E46 has had this repair (6 out of 6 cars).įirst off it’s not the subframe itself that cracks or goes bad.

Possibly even not worth the value of the car. You’ll want address this problem because if it continues to get worse it will become very costly to fix. Is your car knocking when you shift hard or accelerate abruptly? If it sounds like a light thud coming from the rear of the car it could be your rear subframe coming loose behind you. Which means if your car hasn’t had this done, you will be doing it. And the shitty thing is to fully check a car, you have to remove everything in the rear, so you might as well repair it while you have the subframe and all out. I’ve seen it on unmodified cars, early models, late models, low mileage, and high mileage. And it has nothing to do with how modified the car is. But the rear subframe issue is the real Achilles heel of the E46.

Rod bearings, VANOS, or SMG pumps are not uncommon and not cheap or easy repairs. The E46 might be the most popular M3 chassis to mod by enthusiasts, but like all cars, they have their common problems. If you have a BMW E46 or are in the market for a used one, you might have heard of the rear subframe issue.

E46 m3 subframe crack symptoms