Whether you own a BMW 335i, which has a twin-turbo N54, a turbocharged diesel or even have an older BMW turbocharged with an aftermarket kit, a few tips can help a turbocharged motor run more reliably. Thanks to advances in technology, maintaining a turbo is not as involved as it used to be, but forced induction cars do benefit from a little more care than normally aspirated vehicles.
When you start the car, drive easily until the oil has had a chance to warm up. Turbos rely on the engine's oiling system to keep them cool and operating reliably. By avoiding high boost pressures on the turbo while it is warming up, you reduce the wear and tear on the turbos and the motor.
If you have just driven the car hard, especially at a track or on a backroad where you can reach higher rpms for longer periods than you can in normal traffic, let the turbos properly cool before shutting the motor off. What this means is letting the engine idle for as long as a minute to let the temperatures in the turbos cool down.
Because a turbo's impeller spins at many thousands of RPMs, turbochargers create a lot of heat, requiring more frequent oil changes. Most owners of turbocharged cars change their oil as often as every 4,000 to 5,000 miles as preventative maintenance. It is also crucial to use the recommended brand and weight of oil. This usually will be synthetic oil, which is what the BMW factory uses in its new cars.
If you have a turbocharged BMW like a 135i, 335i or 535i and drive the car very aggressively, a good idea is to install a larger aftermarket intercooler. This will greatly reduce the temperatures in the turbo during hard driving, adding to longevity.
