What goes wrong, what it costs, and what to check before you buy a used BMW 4 Series.
The BMW 4 Series occupies a niche position on the UK market.
We track 12 known issues across the BMW 4 Series range, including 1 rated as safety-critical. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a BMW 4 Series? Enter the reg to see which of our 12 known issues apply to that exact car, plus full MOT history and mileage checks.
F32 (2013–2020) — Petrol options included the 2.0 TwinPower Turbo, 2.0 TwinPower Turbo (revised), 3.0 TwinPower Turbo, 3.0 TwinPower Turbo (revised), with 2.0d, 2.0d (revised), 3.0d on the diesel side. We track 6 known issues on this generation, with 4 classified as significant. The most significant concern is Timing chain issues (£1,200–£2,500 to address).
F82 (2014–2020) — Engine options included the 3.0 M TwinPower Turbo. Our database flags 5 known issues on this generation, 1 of which are rated as safety-critical. The most significant concern is Crank hub failure (2014-2016 worst).
G82 (2021–2024) — Engine options included the 3.0 M TwinPower Turbo. 1 known issues affect this generation, none rated as critical. The most significant concern is Oil consumption under hard driving (£100–£200 to address).
The crankshaft hub bolt on S55 engines can loosen over time, allowing the timing gear to slip relative to the crankshaft position. This destroys valve timing and can cause catastrophic internal damage if not caught early. 2014-2016 models are most affected due to inadequate thread locking compound from the factory. BMW issued a service action to inspect and re-torque the hub bolt with improved threadlocker, but not all cars have been updated. This is the most serious documented failure mode on the S55 engine.
If the hub slips significantly, valve timing becomes incorrect and pistons can contact valves, destroying the engine beyond economical repair. A complete engine rebuild typically costs £8,000-£15,000. Early detection allows preventive bolt retorquing for under £500. The car should not be driven if timing slip is suspected.
Listen for any unusual knocking, tapping or rattling from the engine at idle and under load. Check the oil for metal particles or discolouration. On higher-mileage examples, a professional compression test can reveal internal wear before it becomes critical.
The S55 engine consumes oil at higher rates than typical BMW engines, particularly under sustained high-RPM operation such as track driving. The rod bearings can show premature wear patterns, especially in cars driven aggressively or on track. This is documented across the S55 engine family and appears related to oil supply dynamics under high-G cornering and sustained high RPM. Regular oil analysis is recommended to monitor bearing condition before audible knock develops.
Progressive bearing wear leads to oil pressure loss, eventual bearing seizure, and engine destruction. A full engine rebuild with new bearings costs £5,000-£8,000. Early detection allows bearing replacement for £2,000-£3,000. Oil consumption itself requires regular monitoring and top-ups to prevent oil starvation damage.
Listen for any unusual knocking, tapping or rattling from the engine at idle and under load. Check the oil for metal particles or discolouration. On higher-mileage examples, a professional compression test can reveal internal wear before it becomes critical.
The S55 cooling system is stressed by the high heat output of the twin-turbo engine and can fail in multiple ways. The electric water pump can fail without warning, the expansion tank and plastic coolant fittings crack from heat cycling, and the system struggles to maintain temperatures during sustained high-load operation such as track driving. The high-pressure cooling system makes leaks particularly serious as coolant loss is rapid once a failure occurs.
Electric water pump failure causes immediate overheating and can destroy the engine if not caught quickly. Expansion tank or hose failure leads to rapid coolant loss and potential engine damage. Repair costs range from £300 for hose replacement to £1,500 for complete pump and associated component replacement. Overheating damage can require engine rebuild.
Check the coolant level and look for any white residue or staining around hoses, the expansion tank and radiator. After a test drive, check the temperature gauge stayed stable and look underneath for drips. Ask whether key cooling components have been replaced.
The dual-clutch transmission (DCT) in the M4 uses two clutch packs that can wear prematurely under aggressive driving conditions. Early symptoms include judder during low-speed engagement and slipping under hard acceleration. The DCT cooling system can also struggle during track use, leading to overheating and protective power reduction. This is a known limitation of the M-DCT system when used in high-performance applications beyond normal road driving.
Worn clutch packs cause transmission slipping and eventual complete failure requiring clutch replacement. A full DCT clutch service costs £2,000-£5,000 depending on the extent of wear. Overheating can damage transmission internals requiring additional repairs. The car remains drivable with mild clutch wear but performance is reduced.
Check each gear engages smoothly without crunching. Feel the clutch bite point — very high or very low can indicate wear. Listen for bearing noise when the clutch is depressed.
The N20 engine suffers from timing chain stretch and guide wear, particularly affecting earlier production units. The plastic chain guides become brittle and can fragment, while the chain itself stretches beyond the tensioner's ability to compensate. This causes timing retardation, rough running, and potential interference damage if the chain jumps. The later B48 engine addressed these issues with revised guide materials and improved tensioner design.
Complete timing chain failure can cause valve-to-piston contact and engine destruction requiring a full rebuild costing £4,000-£8,000. Early detection allows chain and guide replacement for £1,500-£3,000. The car should not be driven if severe chain rattle is present as sudden failure can occur.
Listen carefully for a rattle or ticking noise from the engine on cold start — this is the most common early sign. Ask for evidence of chain replacement in the service history. On higher-mileage cars without documented replacement, budget for preventative work.
For the full breakdown of all 12 tracked issues with repair costs, see the BMW 4 Series common problems page.
Based on 8k real DVSA MOT tests, the BMW 4 Series fails more often than average on several items. The biggest outlier is wheel with a loose or missing wheel nut, bolt o... at 10x the fleet average, followed by tyre cords visible or damaged (6x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full BMW 4 Series MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 10k miles) typically costs £120–£180 at an independent garage.
The bigger-ticket items to budget for include spark plugs (£200–£300), automatic transmission fluid (£300–£450), dct transmission service (£400–£600).
See the full BMW 4 Series service schedule for every interval and cost breakdown.
The BMW 4 Series has some well-documented weak points, including 1 safety-critical issue that demand careful checking. The right example, properly maintained, can still be a sound purchase — but cutting corners on the pre-purchase inspection is not advisable.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific BMW 4 Series, we cross-reference the exact variant, engine and age against our database of 12 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 12 known BMW 4 Series issues. We are not affiliated with any source listed.