Coolant leaks from the expansion tank / hoses.
Inspect · Check for coolant loss and residue; test the cooling system.

What the known faults on this BMW X5 typically cost to put right at a UK independent garage · use the figures to price risk before you bid, and to justify a reduction when something shows up on inspection.
The single priciest documented job on the 2014–2018 BMW X5 is head gasket / cooling system repair at £900–£2,600. Few cars need every repair listed here · treat £1,480–£5,200 as the full exposure if one arrived with all of them.
Coolant leaks from the expansion tank / hoses.
Inspect · Check for coolant loss and residue; test the cooling system.
Optional air suspension wear / leaks.
Inspect · Check ride height and listen for the compressor cycling.
Oil-filter-housing gasket leak.
Inspect · Look for oil around the filter housing.
N63 V8 oil consumption on 50i models.
Inspect · Check oil level and consumption history on V8 cars.
Ranges are indicative parts-and-labour costs at a UK independent garage, inclusive of VAT. Franchised dealers typically sit 40–80% higher, and prestige or electrified variants sit at the top of each band. Always get a written quote before committing.
Build a tickable checklist for the exact car in front of you, record faults with photos, and hand the buyer a report.