BMW 5 Series G30/G31: Overview, Weak Spots, and Buying Guide
Introduction
The G30 (sedan) and G31 (Touring wagon) are the fifth generation of the BMW 5 Series. The whole family is built on BMW’s modular B-series engines, and the diesel versions come with SCR exhaust aftertreatment using AdBlue urea. The main ownership topics: B58 coolant loss, NOx sensors, the AdBlue system, mild-hybrid components from the LCI onward, and intermittent transmission limp-mode events traced to outdated control unit software.
Strengths and Weaknesses
| Strengths | Weaknesses |
|---|---|
| Modern chassis (optional Integral Active Steering) | AdBlue issues on the diesels can turn expensive |
| iDrive 6/7 with a large touchscreen | B58 coolant loss through the expansion tank and water pump |
| Reliable modular B-series engines | Complex sensor suite: NOx, AdBlue, IBS |
| Efficient ZF 8HP with mild hybrid | Control unit software is critical for stability |
Engines
The entire G30/G31 lineup moved to BMW’s modular B-series engines—the B47, B48, B57, and B58. Diesel versions use the SCR system with AdBlue urea.
The B58 stands out—a gasoline six-cylinder widely regarded as a very reliable engine. The 540i (G30) with this engine is a recommended buy. The only things to keep an eye on: coolant level and whether the control unit software is up to date.
Transmission and Mild Hybrid
At its core is the ZF 8HP eight-speed automatic—an efficient, reliable unit. A mild hybrid arrives with the LCI (facelift). One standalone ownership topic: transmission limp-mode events that appear when the control unit software is outdated.
Suspension and Steering
The G30/G31 chassis is modern. Integral Active Steering is available as an option: the system links the steering to the rear axle and depends on its electronics working correctly.
Electronics and Infotainment
The multimedia system is iDrive 6/7 with a large touchscreen. The car’s sensor suite is complex: NOx sensors, the AdBlue system, IBS—each one a potential source of faults.
Common Problems
B58: Coolant Loss
The known B58 weakness is coolant loss through the expansion tank and the water pump. That’s the key condition check on this engine—both when buying and in everyday service.
AdBlue System (Diesels)
AdBlue issues on the diesels can turn expensive. The tank holds about 22 liters, and range runs 3,700–7,500 miles depending on the model. A dashboard warning tells you when to top up the urea—before the next service is due.
NOx Sensors
The NOx sensors (upstream and downstream of the SCR catalyst) are one of the failure points in the diesel exhaust aftertreatment system.
Transmission Limp Mode
Intermittent transmission limp-mode events appear when the firmware is outdated. Current control unit software is critical for stable operation.
Mild Hybrid
Before buying used, have the mild-hybrid starter-generator (fitted from the LCI onward) checked for unusual noises.
Buying Guide Checklist
- ✓ AdBlue: no codes stored in memory, no “No engine start in XX miles” message