Credov's researched list of the 5 faults the BMW 550i is known for (2003–2010), 3 of them serious or costly. Each one says what to look for when you check the car, so you can spot it before you buy. Not every car has these faults: they are the ones worth checking on this model.
What to look for: Lift the boot floor and spare-wheel cover and look for water, tide marks, rust or green corrosion.
Why it matters: Corroded modules and looms are expensive, and some owners report a battery cable joint overheating; repairs can run from a few hundred dollars up to NZ$6,000 for a burnt loom.
What to look for: Move slowly through P-R-N-D and feel for a thump or delay, then watch for flare between gears on the drive.
Why it matters: A box run on its original fluid can go from flare and harsh shifts to a full rebuild; typically NZ$4,500-$9,000 once it has failed.
What to look for: Start cold, then idle a few minutes and blip the throttle, watching the exhaust for blue-white smoke.
Why it matters: Oil-fouled plugs and rising oil use point to an expensive head job; typically NZ$5,000-$10,000.
What to look for: Feel the console around the iDrive knob, shifter and door pulls for a tacky or peeling coating.
Why it matters: It is cosmetic only, but a sticky, peeling cabin looks tired and worn and buyers notice it immediately when they get in.
What to look for: Look along all window surrounds in good light for haze, white spots or purple fading.
Why it matters: It is purely cosmetic, but it looks shabby on an otherwise tidy car, and the clips on this trim are fiddly and break easily during replacement, so it is a real cost to put right.
Got a question about a BMW 550i? Ask Credov: a noise, a warning light, a part or how to fix it.
On top of the faults above, every Credov inspection covers the basics: fuel smell, leaks or filler rust, engine oil leaks, power steering fluid leak, drive belt cracks or squeal, rust underneath: chassis and mounts, engine mounts, engine oil level and colour, coolant level, colour and leaks, head gasket failure signs, cold start: rattle, knock or smoke, rough or hunting idle, engine running hot on gauge, gearbox or diff oil leak, swapped gearbox without lvv and more.
Researched by Credov from manufacturer recalls and service bulletins, owner reports and workshop sources. Repair prices are typical ranges, not quotes. See also fault codes and repair costs.