What are the defects of the N46 engine?
2 Answers
The N46 engine has issues with oil leaks from the valve cover gasket, cylinder head gasket, and burning oil due to aging valve stem seals. Below are the relevant details: 1. Sealing performance: This engine operates at a temperature of around 110°C. After driving 40,000 to 60,000 kilometers, the sealing performance of some rubber seals deteriorates. 2. Rubber hardening and brittleness: The valve cover gasket, which frequently operates under high temperature and pressure, causes the rubber to harden and become brittle over time, leading to reduced sealing performance and oil leaks from the valve cover gasket. 3. Deterioration of oil seal performance: The decline in sealing performance of the valve stem seals results in severe oil burning in the N46 engine, consuming approximately 1 liter of oil every 1,000 kilometers.
The N46 engine's oil leakage issue is notoriously troublesome, especially around the valve cover—over time, oil seeps out, and if it drips onto the exhaust pipe, there's even a fire risk, so regular seal checks are a must. The VANOS system is also prone to failure, causing sluggish acceleration and shaking, and repairs can cost thousands, which is painful. The high-pressure fuel pump often leaks or makes a buzzing noise, leading to hard starts. Plus, the ignition coils frequently burn out, causing misfires and leaving you stranded on the road, with no choice but to replace them. Severe carbon buildup results in slow cold starts, ruining the driving experience. These problems mean frequent trips to the repair shop for BMW owners. I recommend using high-quality oil and additives during maintenance to mitigate issues and extend the engine's lifespan.
