2018 BMW 4 Series: What to check before buying
Owners have filed 261 complaints with NHTSA about this car, most about the airbags, engine, and electrical. The 9 checks below target those problems, in the order you would do them at the car.
2018- Owner complaints
- 261
- Recalls
- 10
- Crashes reported
- 21
- 23 injuries
Your inspection sheet
Tick items off on your phone at the car, or print it. Ticks stay on this device.
0/9 checked
2018 BMW 4 Series: inspection sheet
Paperwork and questions
Before you go, or before you touch the car0/2
Walk-around and cabin
Engine off, key in hand0/2
Cold start, engine bay, and underside
Ask the seller not to warm the car up first0/3
Test drive
At least 20 minutes, with some highway0/2
These checks are specific to this model year. For tires, body panels, fluids, and the other basics every used car needs, use the general inspection guide.
Which 4 Series is it?
EPA figures for each version of the 2018 BMW 4 Series. Use them to confirm you are looking at the version that was advertised, and as a yardstick on the test drive.
| Version | Drive | EPA rating |
|---|---|---|
| 2.0L 4-cyl | AWD, RWD | 27 mpg |
| 3.0L 6-cyl | RWD | 20 mpg |
- The 2018 BMW 4 Series was sold in two versions. Confirm which one this is from the window sticker, the engine cover, or the VIN report before you compare prices.
- Reset the trip computer at the start of the drive. A 4 Series that averages well under the EPA 20 mpg combined on a mixed route may have an engine or tire problem.
Check the odometer against these mileages
Owners report these failures starting around the mileages below. A car inside one of these ranges deserves a closer look at that part, or records showing it was already fixed.
Coolant leaks and overheating
49,000–53,000 miles
Why these checks: what owners reported
NHTSA complaints for the 2018 BMW 4 Series, grouped by the part owners named. Open a row to read what goes wrong.
Airbags383 crashes
A "Passenger Restraint System Malfunction" warning is the main pattern. The airbag light comes on at random, often with a seat belt chime for an empty seat or one holding only a wallet. Dealers trace it to a failed seat occupancy sensor mat, usually in the passenger seat and sometimes the driver's. Quoted repairs run more than two thousand dollars, and several owners hit it around year six. Separately, three crash reports describe airbags not deploying in front, rear, and animal impacts, with injuries that include a closed head injury.
Engine37No crashes
Sudden coolant loss dominates. The oil filter housing cracks and dumps coolant, with failures reported around 53,000 miles. The low coolant warning comes on only when the tank is nearly empty, then overheating, limp mode, and power loss follow. Plastic coolant hoses and the coolant pump also leak, sometimes at several points at once. Three fire reports describe engine-bay or underbody fires, one right after shutdown. Other reports cover rod bearing failure with metal in the oil and radiators punctured by road rocks. Housing repair quotes reach almost 3,500 dollars.
Coolant leaks lead to overheating, stalling, or lost power while driving. Water pumps fail, sometimes twice on the same car. Coolant hoses and the cylinder head vent line leak, and owners have to keep topping off the reservoir. Warnings like "Drive Moderately" or "Vehicle Will Shut Off" appear before the car loses power, and one report describes smoke filling the cabin. Failures appear between 49,000 and 105,000 miles. Some repairs uncover oil mixing into the coolant or further leaks at the oil housing.
Electrical262 crashes
Fire is the most serious risk here. Two reports describe smoke and flames from the rear window defroster wiring behind the back seat, damaging the headliner and rear deck. Other reports describe a sudden loss of all power, including steering, at very low mileage. Digital gauge clusters flicker or shift until speed can't be read. Bluetooth calls drop again and again, and dealers struggle to fix it. Water getting into the roof shark fin antenna is blamed for emergency call faults. Hybrid owners report battery warnings and shrinking electric range.
Seat belts141 crash
False seat belt warnings and the "Passenger Restraint System Malfunction" message account for most of these reports. Chimes sound for empty seats or for belts that are already buckled. The warnings come and go, sometimes in damp weather, and return after repairs. Dealers blame the passenger seat sensor mat, and owners report repair quotes of more than two thousand dollars. A smaller group describes mechanical faults: driver belts that won't retract, a rear belt that won't latch, and a belt that locked and unlocked over and over during a crash.
Transmission82 crashes
Stalling is the common thread. The engine cuts out at stops or at highway speed, often with a "Drivetrain Malfunction" message. The causes reported include a failed fuel pump and fuel rail, a VANOS fault, and ongoing coolant leaks that bring jerking. Two crash reports describe the car surging out of control, and one left the driver with a fractured back. In another case a service check found a cracked driveshaft flex disc at 22,000 miles.
Seats52 crashes
Faulty seat occupancy sensors trigger the restraint system warning here too. Dealers call for a new passenger seat mat, with one quote above two thousand dollars. Some technicians blame moisture, and owners who found no sign of it dispute that. Other reports describe lumbar support inflating on its own while driving and a driver's seat that slides under braking. In one reversing crash, the driver's seat collapsed backward and the driver suffered serious neck injuries.
Body and structure51 crash
Sunroof glass shatters without warning at highway speed, with a loud bang and glass landing on the shade. Front doors also open by themselves while the car is moving, at speeds as low as 15 to 20 mph. Some owners say no warning came until the door was already open, and one reports it happening twice. The remaining crash report concerns ordinary collision damage, not a defect.
Acceleration and cruise control42 crashes
Sudden unintended acceleration while parking caused two of the crashes reported here, and the cars struck other vehicles or objects. In another report, the cruise control rocker switch sticks and the car keeps speeding up past 80 mph. A run-flat tire blowout on the freeway also appears here. The car shook hard and pulled to one side instead of staying drivable, and it had to be towed.
In owners' own words
Excerpts from complaints 4 Series owners filed with NHTSA, as written. Listen for the same symptoms on your test drive.
Vehicle reports "Passenger restraint system malfunction" upon startup, even when passenger is not in seat. Passenger airbag light turns on. In this state the vehicle defaults to deploying the passenger airbag no matter what, even if passenger weighs less than 45 lbs. BMW of North Scottsdale inspected and recommends replacing the passenger seat sensor mat for $3600, not covered outside of factory warranty.
Filed with NHTSA, October 2022
The Passenger Restraint System Malfunction warning light comes on randomly. Also the passenger side seat belt light comes on even if I put my wallet or something very light on the seat. I previously replaced the driver side seat sensor because the restraint system error was coming on. It seems odd that this critical component would fail in both seats by year six.
Filed with NHTSA, January 2025
My BMW 430i 2018showed no warning and suddenly the car started to shake, I stopped immediately and after the car cooled, there was no coolant, the oil temperature gage was always on normal. The car overheated and caused catastrophic engine failure, and need replacement. Upon inspection by several mechanics, its obvious the coolant leak from a hose that connects with engine block
Filed with NHTSA, March 2024
The vehicle gave a warning that the engine coolant was low and to power down before it overheated. Upon taking it to the dealer, it was discovered that the oil housing unit was defective. After doing online research, this is a very common issue with this part. I had a previous vehicle with a similar issue that caused the vehicle to shut down in traffic from overheating.
Filed with NHTSA, January 2025
KLE MODULE FAILURE - Causing short on EV Hard Wires Wall Charger. Module Burned out on vehicle, which could cause fire and electrical problems. This failure also causes problems with emissions issues as this is a Hybrid Vehicle. BMW has has several issues with this and advising that it is not a covered part in the 2018 module, but has been covered and repaired in 2019 + Vehicles.
Filed with NHTSA, April 2023
Digital display cluster suddenly started flickering and had a shifting image moving incorrectly to the left. It made reading the electronic speedometer and other gauges impossible and highly unsafe while driving on highway. There was no way to safely determine speed or vehicle. The display did not recover after parking the car and restarting engine.
Filed with NHTSA, February 2024
Constantly pops up a message for passenger restraint system malfunction. I had an accident where I swerved off the road into a ditch at about 60 mph. I the driver was not hurt and the passenger wouldn’t have been hurt either if it was for the passenger seat belt not locking correctly at first and then repeatedly locking and unlocking the entire time hurting his chest.
Filed with NHTSA, February 2025
The passenger seat is a mess. There are two issues that repeatedly happen on this car. One - there is false passenger seatbelt warning and two their is a passenger restraint system malfunction message. I took this to the BMW dealership and they said it requires a sensor mat replacement that costs over $2000. I looked it up online and found many people have had the exact same issue with this car.
Filed with NHTSA, January 2024
How the 2018 compares with other 4 Series years
Complaints for this year next to the average for the other model years, area by area.
The 2018 has the most owner complaints of the 8 4 Series years we cover, about 5.7 times the average of the others. Newer years have had less time to collect complaints, so compare like with like.
- Airbags384
- Engine374
- Electrical268
- Seat belts140
- Transmission84
- Seats50
Where the 2018 fits in the 4 Series's history
Redesigns and mid-cycle updates change what can go wrong.
The 2018 is the fifth model year of the 4 Series's first generation (2014–2020).
Recalls to confirm (10)
Recall repairs are free at any BMW dealer, but the seller may never have had them done. Check each campaign number against the VIN.
24V588000EngineAug 2024
BMW of North America, LLC. (BMW) is recalling certain 540d xDrive vehicles that were previously repaired under recall number 22V-614. The exhaust gas recirculation (EGR) cooler may leak internally, causing coolant to mix with diesel engine soot, which could result in smoldering particles and a melting intake manifold.
Risk: An EGR valve with smoldering particles and a melting intake manifold increases the risk of an engine fire.
Fix: Dealers will inspect and replace the EGR module and the intake manifold as necessary, free of charge. Owner notification letters were mailed October 7, 2024. Owners may contact BMW customer service at 1-800-525-7417.
22V614000EngineAug 2022
BMW of North America, LLC. (BMW) is recalling certain 2018 540d xDrive vehicles equipped with an Exhaust Gas Recirculation (EGR) module with an integrated cooler. The EGR cooler may leak internally, causing coolant to mix with diesel engine soot, which could result in smoldering particles and a melting intake manifold.
Risk: A melting intake manifold increases the risk of fire.
Fix: Dealers will replace the EGR module, and the intake manifold will be inspected and replaced, if necessary, free of charge. Interim owner notification letters were mailed on October 7, 2022. Owner notification letters were mailed December 30, 2022. Owners may contact BMW customer service at 1-800-525-7417.
21V907000Fuel systemNov 2021
BMW of North America, LLC (BMW) is recalling certain 2013-2018 328d, 328d xDrive, 2014-2018 328d Sports Wagon, 328d xDrive Sports Wagon, 2014-2016 535d, 535d xDrive, 2015 740Ld xDrive, 2015-2017 X3 xDrive28d SAV, and 2014-2017 X5 xDrive35d SAV diesel vehicles equipped with an Exhaust Gas Recirculation (EGR) module with an integrated cooler. The EGR cooler may leak internally, causing coolant to mix with diesel engine soot, which could result in smoldering particles and a melting intake manifold.
Risk: A melting intake manifold increases the risk of a fire.
Fix: Dealers will replace the EGR cooler and inspect the intake manifold, replacing it as necessary, free of charge. This recall includes all vehicles previously recalled under 18V-755. Vehicles previously recalled under 18V-755 will need to have the new remedy performed for this recall. An interim owner notification letter was mailed on January 18, 2022. The remedy is expected to be available in June 2022. Owner notification letters were mailed on July 6, 2022. Owners may contact BMW customer service at 1-800-525-7417.
21V586000Fuel systemJul 2021
BMW of North America, LLC (BMW) is recalling certain 2014-2018 328d, 328d xDrive, X5 xDrive35d, 2014-2016 535d, 535d xDrive, 2015 740Ld xDrive, and 2015-2017 X3 xDrive28d vehicles. The high-pressure fuel pump may fail.
Risk: Fuel pump failure can cause an engine stall while driving, increasing the risk of a crash.
Fix: Dealers will replace the high-pressure fuel pump, free of charge. Owner notification letters were mailed on January 14, 2022. Owners may contact BMW customer service at 1-800-525-7417.
20V243000AirbagsApr 2020
BMW of North America, LLC (BMW) is recalling certain 2017 530i, 530i xDrive, 540i and 540i xDrive and 2017-2018 530e xDrive vehicles. Prior exposure to excessive levels of humidity within the driver and passenger head air bag inflators may affect the proper deployment of the head air bags.
Risk: In the event of a crash of sufficient severity, deployment of the head air bag may be impaired and/or the igniter could separate from the inflator, increasing the risk of injury.
Fix: BMW will notify owners, and dealers will replace the left or right head air bag, free of charge. The recall began June 24, 2020. Owners may contact BMW customer service at 1-800-525-7417.
19V684000Backup cameraSep 2019
BMW of North America, LLC (BMW) is recalling certain 2018 540d, 2018-2020 530i, 530i xDrive, 540i, 540i xDrive, M550i xDrive, M5, 530e, 530e xDrive, X3 sDrive, X3 xDrive, X3 M40i, X3 M, and 2019-2020 X4 xDrive, X4 M40i, X4 M, X7 xDrive, X7 M50i, 740Li, 740Li xDrive, 750Li, 750Li xDrive, 8 Series Convertible and Coupe 840i, 840i xDrive, M850i xDrive, X5 sDrive, X5 xDrive, X5 M50i, X6 xDrive, X6 M50i, 330i, 330i xDrive, M340i, M340i xDrive, Z4 sDrive, Z4 M40i, 740Le xDrive and 745Le xDrive, 2018-2019 640i xDrive Gran Turismo and Rolls-Royce Phantom, 2019 M850i xDrive Gran Coupe and Rolls-Royce Cullinan and 2020 Toyota Supra vehicles. The back-up camera and display settings can be adjusted such that the rear view image is no longer visible and the system will retain that setting the next time the vehicle is placed in reverse. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 111, "Rearview Mirrors.".
Risk: The lack of an image in the back-up camera display increases the risk of a crash.
Fix: BMW will notify owners, and dealers will update the back-up camera software, free of charge. The recall began November 8, 2019. Owners may contact BMW customer service at 1-800-525-7417 or Rolls-Royce at 1-877-877-3735. Toyota owners may contact Toyota customer service at 1-888-270-9371.
18V755000EngineOct 2018
BMW of North America, LLC (BMW) is recalling certain 2013-2018 BMW 328d and 328d xDrive, 2014-2018 328d Sports Wagon and 328d xDrive Sports Wagon, 2014-2016 535d and 535d xDrive, 2015 740Ld xDrive, 2015-2017 X3 xDrive28d SAV and 2014-2017 X5 xDrive35d SAV vehicles equipped with an Exhaust Gas Recirculation (EGR) module with an integrated cooler. If the EGR cooler leaks internally, the coolant can mix with diesel engine soot. The high EGR temperatures may result in these particles possibly smoldering and melting the intake manifold.
Risk: The melting intake manifold can increase the risk of a fire.
Fix: BMW will notify owners, and dealers will inspect and replace the EGR cooler as necessary. If a leak has already occurred, the engine intake manifold will also be replaced. These repairs will be made free of charge. The recall began May 13, 2019. Owners may contact BMW customer service at 1-800-525-7417.
18V652000EquipmentSep 2018
BMW of North America, LLC (BMW) is recalling certain 2018 BMW 330e iPerformance, i3 Rex, i3 Sport Rex, X5 xDrive40e, i3 BEV, i3 Sport BEV and 2019 i8 and i8 Roadster vehicles and 2018-2019 530e iPerformance, 530e xDrive iPerformance and 740Le xDrive iPerformance vehicles. Capacitors within the TurboCord Portable Chargers may fail, possibly resulting in a shock hazard or a fire.
Risk: An electrical shock or a fire can increase the risk of injury or death.
Fix: BMW will notify owners, and dealers will inspect the charging cable, and replace it if necessary, free of charge. The recall began February 22, 2019. Owners may contact BMW customer service at 1-800-525-7417.
18V465000EngineJul 2018
BMW of North America, LLC (BMW) is recalling certain 2018 BMW 540d xDrive vehicles. The crankshaft sensor may be equipped with incorrect firmware, preventing the sensor from properly processing input from the crankshaft reluctor ring, possibly resulting in a vehicle stall. On September 12, 2018, BMW expanded the recall to a total of 5,309 vehicles including certain 2018-2019 BMW 540d xDrive, 230i M240i, M240i xDrive, X2 sDrive28i, X2 xDrive28i, X1 sDrive28i, X1 xDrive28i, 330i, 330i xDrive, 340i, 340i xDrive, 330i xDrive Gran Turismo, 530i, 530i xDrive, 540i, 540i xDrive, 530e, 530e xDrive, 640i xDrive Gran Turismo, 330e, 2019 430i Gran Coupe, 430i xDrive Gran Coupe, 440i Gran Coupe, 440i xDrive Gran Coupe, 430i, 430i xDrive, 440i, 440i xDrive, 740i, 740i xDrive, MINI Cooper, Cooper S, JCW, MINI Countryman (Cooper, Cooper All4, Cooper S, Cooper S All4, JCW All4), and MINI Clubman (Cooper, Cooper S, Cooper All4, Cooper S All4, JCW All4) vehicles.
Risk: A vehicle stall can increase the risk of a crash.
Fix: BMW will notify owners, and dealers will replace the crankshaft sensor, free of charge. The recall began September 6, 2018. Owners may contact BMW customer service at 1-800-525-7417.
17V507000Seat beltsAug 2017
BMW of North America, LLC (BMW) is recalling certain 2018 430i, 430i xDrive, 440i, 440i xDrive, and M4 convertible vehicles. The Emergency Locking Retractors (ELR) within the front seat belt assemblies may have been produced with incompatible vehicle-sensitive locking mechanism housings.
Risk: If the vehicle has an incompatible vehicle-sensitive locking mechanism, the seat belt may not restrain the seat occupant in the event of a crash, increasing the risk of injury.
Fix: BMW will notify owners, and dealers will inspect and, if necessary replace, the front seat belt assemblies, free of charge. The recall began October 13, 2017. Owners may contact BMW customer service at 1-800-525-7417.
Also looking at these instead of a 4 Series?
Cars shoppers compare with the BMW 4 Series, with their own 2018 checklists.
2018 owner complaints, side by side
- Chevrolet Camaro75
- BMW 5 Series212
- Mercedes-Benz E-Class252
- 2018 BMW 4 Series261
- Mercedes-Benz C-Class518
