1. Turbocharger & Boost Pressure Issues(All Generations)
Symptoms: Engine warning light, power loss, whistling or hissing noise during acceleration, stalling at idle, increased fuel consumption
Typical Mileage: 60,000–120,000 miles
Repair Cost: £800–£2,500 (turbocharger repair or replacement; wastegate valve repair)
Replacement Cost: £4,000–£7,000 (if ignored — full engine replacement)
Urgency: Check — book inspection urgently if you hear whistling or experience power loss
Our recommendation:
Boost pressure issues are a common complaint on the 740d across all generations. Symptoms include an engine light, power loss, a whistling noise during acceleration, stalling at idle, and increased fuel consumption. One owner reported that a 2016 740d experienced power loss, rough running, hissing, and increased fuel consumption. In some cases, the problem is a faulty wastegate valve. If you experience these symptoms, have the turbo system inspected immediately — a £800–£2,500 repair is far cheaper than the engine damage that can follow if ignored.



