Engine

COMMON PROBLEMS: Oil Leaks, Valve Cover Gasket Leaks, Oil Filter Housing Leaks, Oil Consumption, Misfires

Oil leaks are the big one here. The valve cover gasket and the oil filter housing gasket both harden up over time and start to weep. You usually smell it before you see it. That burnt smell when oil hits something hot after a drive. Some of these engines burn oil on top of leaking it, so the level drops between changes with nothing on the ground to show for it. The turbo motors run hot, and heat is what cooks those gaskets to begin with. Misfires sneak in as the plugs and coils wear.

Cooling System

COMMON PROBLEMS: Electric Water Pump Failure, Coolant Leaks, Overheating, Thermostat Failure, Expansion Tank Cracks

The 5 Series runs an electric water pump, and owners usually know the term by the time they call us. It can quit with almost no warning, and the temperature climbs fast when it does. The plastic parts don't help the odds any. The expansion tank and the thermostat housing go brittle over the years and crack, and coolant starts seeping out at the seams. A sweet smell in the driveway or a low coolant light is worth catching early, because overheating one of these engines can cause serious damage in a hurry.

Fuel System

COMMON PROBLEMS: High-Pressure Fuel Pump Failure, Hard Starting, Misfires, Rough Idle, Check Engine Light

The high-pressure fuel pump is the weak link on the turbo engines. When one starts to go, you get a hard start, a stumble, maybe a check engine light, along with a misfire. Feels a lot like an ignition problem. That's the trap. People chase coils and plugs when the pump was the real cause all along. A weak one tends to act up worst when the tank's low or the engine's already hot.

Electrical System

COMMON PROBLEMS: Window Regulator Failure, Battery Drain, Warning Lights, iDrive Glitches, Sensor Faults

There's a ton of electronics in a 5 Series, so there's a lot that can act up. Window regulators are a classic. The glass drops and won't come back, or it stops halfway. Batteries drain overnight when something won't go to sleep. Warning lights blink on and disappear. The iDrive screen freezes or reboots on its own. Sometimes it is a dying battery or a bad ground, and sometimes it's a sensor or module that needs attention.

Suspension

COMMON PROBLEMS: Control Arm Bushing Wear, Clunking Noise, Uneven Tire Wear, Steering Vibration, Rough Ride

Front control arm bushings usually go first. You'll hear a clunk over a driveway lip or a speed bump, and the steering starts feeling a little vague off center. Once those bushings wear, the alignment drifts, the tires scrub off unevenly, and you pick up a shimmy in the wheel at freeway speed. A car that felt smooth when it was newer starts feeling loose and busy on rough pavement.