The BMW 4 Series F32 is one of the most popular models in BMW’s modern range. Combining sporty looks, impressive performance and everyday practicality, the F32 Coupe has become a favourite among drivers looking for a car that offers both luxury and driving enjoyment. However, like any used car, it has its weaknesses, and there are several common problems that owners and potential buyers should be aware of.
Produced from 2013 (as 2014 year model) to 2020, the F32 shares much of its mechanical architecture with the BMW 3 Series F30. This means that many of the reliability issues found in the 3 Series can also affect the 4 Series. While the F32 can be a reliable car when properly maintained, certain components are known to wear out or fail, potentially resulting in expensive repairs.
Here are five of the most common things that can go wrong with a BMW 4 Series F32.
1. Timing Chain Problems
One of the most important issues to be aware of when buying an F32 is timing chain wear, particularly on models fitted with the earlier N20 2.0-litre petrol engine.
The N20 engine, commonly found in the 420i and 428i, has a known weakness involving its timing chain guides and oil pump drive chain. Over time, the plastic guides can wear, become brittle and eventually break. The timing chain can then become loose, potentially jumping teeth or causing catastrophic engine damage.
The main symptoms to look out for include:
– Metallic rattling noises during cold starts.
– A whining noise coming from the front of the engine.
– Rough engine operation or warning lights.
– Engine timing-related fault codes.
It is worth noting that not every F32 has this problem. Later B48 petrol engines are generally less affected by the original N20 timing chain issues. However, early diesel models fitted with the N47 engine also deserve attention because of their own timing chain weaknesses.
If you are considering buying an early 420i, 428i or 420d, check whether the timing chain has previously been replaced or inspected. A documented replacement is a significant advantage. Ignoring unusual engine noises can turn what could have been preventative maintenance into a very expensive engine repair.
2. Cooling System and Water Pump Failure
Cooling system problems are another issue worth keeping an eye on when owning a BMW F32. BMW uses electrically controlled water pumps on many of its petrol engines, and these components can eventually fail with age and mileage.
Unlike traditional mechanical water pumps, an electric water pump can fail without giving much warning. When this happens, coolant circulation can be reduced or stopped completely, causing the engine to overheat.
Other cooling system components can also cause trouble, including thermostats, expansion tanks, coolant hoses and plastic connectors. Over time, heat cycles can make plastic components brittle, resulting in coolant leaks.
Common symptoms include:
– Coolant level warnings on the dashboard.
– Engine temperature warnings.
– Coolant smell after driving.
– Visible coolant leaks underneath the vehicle.
– Cooling fans running excessively.
The best approach is to inspect the cooling system regularly and investigate any unexplained coolant loss. A pressure test can help identify leaks that are difficult to see.
Replacing a failing water pump before it causes overheating is considerably cheaper than dealing with potential engine damage.
3. Oil Leaks from the Engine
Oil leaks are relatively common across BMW’s F-series models, and the F32 is no exception. As the vehicle gets older, rubber seals and gaskets begin to deteriorate, allowing engine oil to escape.
One of the most common areas to inspect is the oil filter housing gasket, particularly on models equipped with the N55 engine, such as the 435i.
Another common source of oil leaks is the valve cover gasket. This gasket seals the top of the engine, and when it starts to deteriorate, oil can escape and accumulate around the engine.
The most noticeable symptoms include:
– Burning oil smells, especially after driving.
– Oil residue around the engine.
– Oil spots underneath the vehicle.
– Smoke coming from the engine bay.
– Gradually decreasing engine oil levels.
Oil leaks should never be ignored. For example, on the N55 engine, oil leaking from the oil filter housing can reach the auxiliary belt. If the belt becomes contaminated, it can deteriorate and potentially cause further engine damage.
When inspecting a used F32, look carefully around the oil filter housing, valve cover and underneath the engine. A clean engine is not necessarily a guarantee of good condition, so checking for fresh oil residue is important.
4. Suspension Bushes and Control Arms
The BMW 4 Series is designed to offer a sporty driving experience, which means its suspension components have to deal with considerable forces during everyday driving.
As the F32 gets older, suspension bushes and control arms can begin to wear. This is particularly noticeable on vehicles that have covered higher mileage or regularly travel on poor-quality roads.
Front control arm bushes and thrust arm bushes are among the components worth checking. When the rubber deteriorates, it can create unwanted movement in the suspension, affecting both comfort and handling.
Typical symptoms include:
– Clunking noises when driving over bumps.
– Vibrations through the steering wheel.
– Steering that feels less precise.
– Uneven tyre wear.
– Instability during braking.
Rear suspension components can also develop wear, so it is important not to focus exclusively on the front axle.
Fortunately, suspension problems are generally less serious than engine failures, but worn bushes can significantly affect how the car drives. During a test drive, pay attention to any unusual noises and whether the steering feels tight and predictable.
A proper inspection on a vehicle lift is the best way to identify worn suspension components before purchasing the car.
5. Diesel EGR and DPF Problems
For buyers considering a diesel F32, particularly the popular 418d and 420d models, EGR and DPF problems are worth understanding.
The exhaust gas recirculation (EGR) system redirects some exhaust gases back into the engine to reduce emissions. Over time, carbon deposits can build up inside the EGR valve and associated components, affecting their operation.
The diesel particulate filter (DPF) is designed to capture soot from the exhaust. It periodically regenerates by raising its temperature and burning off accumulated soot.
However, vehicles that mainly make short journeys and spend most of their time in urban traffic may struggle to complete this regeneration process. Eventually, the DPF can become excessively blocked.
Symptoms of these problems include:
– Engine management warning lights.
– Reduced engine performance.
– Increased fuel consumption.
– Frequent or unsuccessful DPF regeneration.
– Limp mode or restricted engine power.
EGR cooler leaks are another concern on certain BMW diesel engines, and some vehicles have been subject to safety recalls relating to the EGR cooler. Buyers should always check the vehicle’s VIN for outstanding recalls.
If you regularly drive longer distances, a diesel F32 can be an excellent choice. However, for predominantly short urban journeys, a petrol model may be more suitable.
Is the BMW F32 Reliable?
Despite these potential problems, the BMW F32 4 Series is still a very appealing car and can be a reliable daily driver when properly maintained.
The most important thing is understanding which engine your car has, as different versions come with different weaknesses. Early N20 petrol and N47 diesel engines deserve particular attention because of their timing chain issues, while newer B48 and B58 engines generally offer a better starting point.
Before purchasing one, always check its service history, inspect the engine for oil and coolant leaks, listen for unusual noises and arrange a professional pre-purchase inspection.
Buying a well-maintained F32 with a documented service history is far better than choosing a cheaper example with an unknown maintenance background. A little research before buying can save you thousands in unexpected repair bills.
