The 2005+ 3-Series is heavier, more powerful and has way more technology than previous generations. In general, they are as reliable as their predecessors, but they do have some common issues.
Suspension and Shocks
Unlike some of the older 3-Series cars, the suspension systems have, so far, only shown issues with the Thrust Arm Bushings. Shocks are still a wear item and should be considered marginal by 60k.
Most folks who have been driving their cars since new hardly notice the deterioration as it is gradual. Thrust arm bushing failure will typically reveal itself as a shimmy under braking and possibly a low-speed knock if you get on and off the throttle quickly.
Shock failure symptoms include: Diving under braking and acceleration, excessive lean and suspension compression during cornering. Bouncy and uncomfortable ride. Shocks and struts may visibly leak shock oil. EDGE generally recommends replacing the factory units with quality shocks from Koni or Bilstein whenever possible. When replacing shocks and struts, keep in mind it is a great time to install lowering springs or freshen up other areas of the suspension. You will be amazed at the difference a good set of shocks can make in both comfort and performance!
The six-cylinder cars are still prone to leaking valve cover gaskets. They leak externally, but also leak internally and can fill the spark plug holes with oil. This can fry coil packs. Other messy leaks can include the oil filter stand gasket, oil cooler gasket, and oil vapor separator hoses.
Of particular concern is the transmission pan and sealing sleeve. The pans tend to warp over time (not sure why) and the only sure way to fix the leak is to replace the pan. BMW does not call for or recommend transmission fluid changes, this may prove problematic in the long term, but the transmissions seem to last well over 100k miles.
BMW Cooling Systems are definitely their Achilles heel. For some unfortunate reason BMW chooses to use plastic in MANY critical areas of the cooling system. The plastic heat cycles out and becomes brittle. That, coupled with normal vibration is a recipe for disaster.
Common failure points include the expansion tank (cracks at the seams), thermostat failure (these are electronic, so it will cause check engine light), water pump failure (electric water pumps will quickly cause an overheat), radiator leaks at the end tanks, and any of the quick disconnect hoses.
The Turbocharged (335) cars are VERY prone to overheating at the track, especially on hot days. Between the intercooler, oil cooler and radiator there is too great an airflow requirement for the car design to deliver. For this unfortunate reason, the 335 (and its 135/535 cousins) don’t make good track car choices.
V8 M3s have a few issues of note. Several of these cars have had (or will have) their differentials replaced for noise and knocking sounds. A few cars that we know of have had their heads removed and something done inside, but the dealer is not forthcoming about the fix. Many folks have had complaints about the smoothness of the DCT trans, but that is to be expected in traffic. No major failures have crossed through our bays.
BMW service indicator-recommended 15k mile service intervals are causing internal engine wear. BMW has a Technical Service Bulletin indicating that dirty engine oil causes cam ledges to become worn down and causes oil to get through. This will cause, poor running, excessive engine noise and will eventually throw a check engine light. Because of these issues, we are recommending that customers perform regular oil changes at 7-8k miles max. BMW knows that the engines will last 100k even with this advanced wear, but that gets your car out of warranty and therefore it’s not an issue for them. We know that you want your car to last, so a little extra maintenance will go a long way! In addition to the extended intervals causing cam ledge wear, the VANOS solenoids are becoming clogged with oil sludge and debris causing rough running and check engine lights. We have been able to successfully remove these solenoids and clean them without additional repairs being needed.