Ford Focus ST Mk3 Diesel Buying Guide
Ford Focus ST Diesel Mk3.5 Buyers Guide
The Ford Focus ST Diesel Mk3.5, produced from around 2015 to 2018, offers a blend of performance and efficiency, combining the popular ST performance credentials with the fuel economy benefits of a diesel engine. Powered by the 2.0-litre EcoBlue engine, the ST Diesel Mk3.5 delivers impressive torque and a strong driving experience, while also maintaining lower running costs compared to its petrol counterpart. If you’re considering buying one, here’s what you should look out for.
1. Engine and Performance
The 2.0-litre TDCi engine in the Focus ST Diesel Mk3.5 produces around 185 bhp and 400 Nm of torque. This offers strong acceleration and an engaging drive, particularly for those looking for a balance of performance and efficiency.
When buying, check the engine’s health by ensuring it starts easily and runs smoothly without any unusual noises, such as knocking or excessive vibrations. Diesel engines naturally have a bit of clatter, but excessive noise or rough idling could indicate issues such as injector problems or fuel system malfunctions.
Turbocharger and Boost Issues
Like many diesel-powered performance vehicles, the turbocharger is a critical component of the Focus ST Diesel. Be aware of potential turbocharger issues, including excessive smoking or lag during acceleration, as this can be a sign of a failing turbo or a boost leak. It’s always a good idea to have the car checked by a professional if you notice any abnormal performance.
Common Diesel Issues
Diesel engines can experience specific issues over time, such as problems with the diesel particulate filter (DPF), EGR (Exhaust Gas Recirculation) valve, or injectors. The DPF can become clogged, particularly if the car is used for short journeys where it doesn’t have a chance to regenerate properly. If you’re considering a used model, check the service history to see if the DPF has been cleaned or replaced.
The EGR valve can also become clogged over time, causing poor engine performance or even the triggering of warning lights. If the car has been well-maintained with regular servicing, these issues may be less likely to occur, but it’s still worth keeping in mind.
2. Transmission and Clutch
The Focus ST Diesel Mk3.5 comes with either a 6-speed manual or a 6-speed automatic transmission. Both gearboxes are generally reliable, but the manual transmission can wear if the car has been driven aggressively or has high mileage.
If you’re considering a used manual, check for any signs of a slipping clutch, such as a soft or spongy pedal or difficulty engaging gears. If the car has a dual-mass flywheel (common in diesel vehicles), listen for any unusual noises when the clutch is engaged or disengaged, as this could indicate flywheel wear or failure. It is relatively common for tuned cars (Stage 1, Stage 2) to experience judder when pulling away, this is a sign that your flywheel requires replacement.
You can find a full list of our drivetrain options for the Mk3.5 Diesel ST here
For the automatic version, ensure smooth gear changes and check for any hesitation or harsh shifting. Transmission fluid should be checked regularly, and low fluid levels can cause poor shifting and potential damage to the gearbox.
3. Suspension and Steering
The Focus ST Diesel Mk3.5 features a sportier suspension compared to the standard Focus, providing a balanced ride and better handling. The suspension components are generally durable, but if the car has been driven hard, especially on uneven or rough roads, you should check for worn-out parts.
Look for signs of worn shock absorbers or struts, which can affect ride comfort and handling. A suspension inspection should include checking the condition of the bushings, sway bars, and ball joints, all of which can wear over time. If the car has any unusual noises, such as clunking or knocking while driving over bumps, it may be an indication that suspension components need attention.
The steering should feel precise, with no play in the wheel. If you notice any steering pull or vibrations, it could indicate issues with the steering rack or alignment.
4. Brakes
The Focus ST Diesel Mk3.5 is equipped with larger brakes than the standard Focus to match its performance potential. Check for even wear on the brake pads and discs, particularly if the car has been driven enthusiastically.
Listen for any squeaking, grinding, or pulsation during braking, which could signal worn brake pads or discs. A full inspection of the brake system, including checking the brake fluid levels and condition, is recommended. If the car has had brake work done recently, ask for any records of part replacements.
5. Interior and Electronics
The interior of the Focus ST Diesel Mk3.5 is well-appointed with sports seats, a good infotainment system, and quality materials. However, as with any used car, ensure that all electronics are functioning correctly. This includes checking the infotainment system, climate control, electrical windows, and heating. Pay particular attention to the condition of the SYNC system, as problems with software or connectivity can sometimes arise with older units.
Make sure that there are no signs of excessive wear on the seats, especially on the bolsters, as this can be an indicator of heavy use. The steering wheel and gear knob should also be checked for excessive wear, as these areas tend to show signs of use quicker.
6. Service History and Timing Belt
Always ask for the car’s full service history when considering a purchase. Regular servicing is critical to keeping the ST Diesel Mk3.5 in good condition, particularly when it comes to maintaining the engine, turbo, and fuel system.
The timing belt (or timing chain, depending on the specific model) should be inspected for wear, as it’s crucial to the engine’s operation. Ford typically recommends replacing the timing belt around 100,000 miles (160,000 km), so check if this service has been done on higher-mileage cars. Neglecting this service can lead to severe engine damage if the belt fails.
7. Fuel Economy and Emissions
One of the key selling points of the Focus ST Diesel Mk3.5 is its balance of performance and fuel efficiency. The EcoBlue engine offers impressive mpg figures, typically around 50-60 mpg (depending on driving style and conditions). When buying, check the car’s fuel economy based on the previous owner’s driving habits. If the car has been driven mostly on short trips, it may not have had the opportunity to show its true fuel economy potential.
Additionally, ensure that the car’s emissions system is functioning properly, particularly the DPF and EGR valve, to avoid any costly repairs or MOT issues.
8. Common Issues and Recalls
Before purchasing any used vehicle, it's a good idea to check for any recalls or outstanding safety issues that may need addressing. The Focus ST Diesel Mk3.5 may have had some recalls for minor issues, so verify that any necessary work has been completed. You can check this with the seller or through a Ford dealership using the car’s registration number.
Conclusion
The Ford Focus ST Diesel Mk3.5 is an excellent choice for those looking for a sporty yet efficient daily driver. However, as with any used car, there are specific areas to check to ensure you’re getting a well-maintained vehicle. Pay attention to the engine’s health, the condition of the suspension and brakes, and the state of the interior electronics. A solid service history and attention to key maintenance tasks, such as the timing belt and DPF, are essential for a successful purchase. By doing your homework and ensuring the car has been well cared for, the Focus ST Diesel Mk3.5 can provide a great combination of performance, practicality, and fuel economy for years to come.