Thinking about buying a used BMW 4 Series (2013–2020) in New Zealand? We've documented 6 known faults for this model spanning engine, transmission, and fluid leaks. Each researched and verified before it's published. The most serious issues here are rated critical. Two are set out in full below — the rest, with the symptoms, repair costs and checks for each, are free with an account.
6
Documented faults
Critical
Most serious
$1,200–$4,000
Typical repair
3
Systems covered
Known BMW 4 Series faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
01B47 diesel timing chain and tensioner failure
CriticalOccasionalEngine $3,500–$8,000 to fix
The B47 2.0-litre diesel used in 418d, 420d and 425d is afflicted by a documented timing chain stretch and tensioner failure pattern, predominantly at the rear of the engine where the chain is driven from the rear of the crankshaft. Cold-start chain rattle progresses to jumped timing and catastrophic engine damage if not addressed. BMW issued a recall in several European markets. The repair requires transmission removal, making it a significant labour job.
Symptoms to notice
Rattling noise on cold start from rear of engine, may clear after warm-up
Persistent chain rattle at idle that does not clear
Check Engine light with camshaft-crankshaft correlation fault codes
Engine stall or sudden loss of power if chain jumps
What to check
Cold-start the engine and listen carefully for chain rattle from the engine lower/rear area. Check for fault codes relating to cam timing. Review full service history and ask whether chain or tensioner has been inspected. Diesel 4 Series are less common in NZ but more prevalent in AU market.
Where to look: Timing chain at rear of B47 engine block (transmission-side), chain tensioner and plastic guide rails
Ask the seller
“Has the timing chain been inspected or replaced?”
“Does the engine rattle on cold start before it warms up?”
“Has it been serviced at correct intervals using correct oil viscosity?”
02B48 oil cooler gasket leak
MajorCommonFluid Leaks $600–$1,300 to fix
The B48 2.0T engine uses a thermoplastic oil-to-coolant heat exchanger mounted on the block. The integrated gasket and O-ring seals degrade with thermal cycling, causing engine oil to weep into coolant or externally at the cooler housing. Documented across 3 Series, 4 Series and X3/X4 with B48. Common after 80,000 km. The B48 replaced the N20 in the 420i/430i from the 2016 LCI onwards and continues into the G22 generation.
Symptoms to notice
Oil in coolant reservoir (brown or milky tinge on cap underside)
External oil seepage around oil cooler housing area below the oil filter
Coolant consumption without visible external leak
Gradual oil level drop with no obvious drips on ground
What to check
Remove engine undertray and inspect oil cooler housing on the right-hand side of the block for oil staining. Check coolant reservoir cap underside for oil contamination. Inspect oil filter housing gasket simultaneously as it fails in the same area.
Where to look: Oil cooler housing on right-hand side of B48 engine block, adjacent to the oil filter housing
Ask the seller
“Has the oil cooler gasket or housing ever been replaced?”
“Have you noticed oil in the coolant or unexplained coolant consumption?”
“Has the car had any coolant-related work done?”
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TransmissionMajor
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4 more documented faults on the BMW 4 Series
Symptoms, what to check, where to look and what to ask the seller — for every fault above. Free with an account, no card needed. One account covers one vehicle, so make it the car you’re actually looking at.
This page covers the model. Enter the plate of the actual car you’re looking at and see its year, engine, safety rating and register flags — free, no account needed.
Like any used car, it depends on the specific example and its service history. Across the 6 documented faults for the BMW 4 Series, the recurring problem areas are engine, transmission, and fluid leaks. A BMW 4 Series with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.
What are the most common problems with a used BMW 4 Series?
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We've catalogued 6 known faults for the BMW 4 Series, covering engine, transmission, and fluid leaks. Two are written out in full on this page. The rest — with the symptoms to notice, what to inspect, and typical repair costs for each — are free once you create an account.
How much do repairs cost on a BMW 4 Series?
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Most single repairs on the BMW 4 Series fall between $1,200–$4,000 at NZ independent-workshop rates. Some of the 6 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.
Should I get a pre-purchase inspection on a BMW 4 Series?
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Yes. A BMW 4 Series inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $17.90 far less than the cost of missing one of the faults on this page.