Common problems with BMW E46s
The E46 generation of the BMW 3 Series was sold in North America from 1999 to 2005. The platform offered a wide range of vehicles including wagons, coupes, sedans and convertibles in both rear-wheel drive and all-wheel drive, with a variety of four and six cylinder engines.
This era also saw the introduction of the legendary E46 M3, which has become highly desirable in the years since it went out of production.
In general, the E46 generation was quite reliable. Part of this can be attributed to the relative simplicity of these cars, especially compared to modern BMWs. That being said, there are some common problems that are seen around this time. With some examples over 20 years old, these problems are more common.
In this article, we will go over the most common problems seen in BMW E46 3 Series.
Oil filter housing
On inline 6 engines of this era, the oil filter housing is located on top of the engine, next to the intake manifold (driver’s side) at the front. Countless heat cycles and years of operation cause the gasket to harden, leading to leaks. If the leak is severe, you will notice oil in the front of the engine block on the driver’s side around the housing. Replacing the housing seals will fix this problem.
VANOS problems
VANOS is BMW’s variable valve timing system and was first introduced on the E36 platform in the early 1990s. When the E46 went into production, VANOS systems were common on many BMW engines. The VANOS system dynamically controls intake and exhaust valve timing, resulting in improved drivability and performance throughout the RPM range.
VANOS problems usually present themselves as rough running, excessive noise, and a noticeable loss of power at certain RPMs. VANOS systems incorporate moving parts and gaskets that can wear out over time and need to be replaced.
Throttle body actuator
This problem is common on the S54 engine. The S54 used Individual Throttle Bodies (ITBs), which control air intake to each cylinder individually. ITBs are controlled by a single rod and actuator. The actuator may have problems or fail completely and need to be replaced.
S54 engine bearings
This problem is seen in the E46 M3. The high-performance nature of the S54 inline-six puts a lot of stress on the engine’s internal components. Unfortunately, the engine bearings will wear and need to be replaced around 60,000 miles.
Combination valve problems
The combined valve is part of the crankcase ventilation system. Inside the valve, there is a diaphragm that can break and start leaking. If this happens, the car can throw lean misfires, have drivability problems, and emit a hissing noise from the engine compartment.
Cooling system leaks
The plastic components of the BMW E46 cooling system are prone to becoming brittle and cracking. The resulting loss of coolant can cause the engine to overheat, which can lead to catastrophic engine failure.
Cold weather crank vent kit
If your car originated in a warm state, but now lives in a place that regularly sees colder temperatures, it’s a good idea to upgrade your crankcase ventilation system to a cold weather kit. The cold weather kit protects against condensation that can cause the pipe to freeze and crack. If this happens, the car will have vacuum leaks and performance problems.
window lifters
The window winders are responsible for moving the windows up and down when activated by the motor or the window handle. In BMW E46s, they are prone to problems. Lack of maintenance, poor design and delicate components contribute to failure.
When a regulator fails, the window may become stuck, misaligned, or make strange noises when it moves up and down. Fortunately, this issue is more of a nuisance than a danger. Replacing the regulator will restore the functionality of the windows.
Having problems with your E46? Come to Alex’s Autohaus!
Whether you’ve had your E46 for years or just picked one up as a project, the BMW experts at Alex’s Autohaus are here to help. Our technicians use factory diagnostic equipment and OEM parts in all of our repairs, ensuring your car runs as it’s supposed to. Call us or schedule an appointment online today!
