Quick service recommendations
- Standard road car: Service every 12 months or 12,500 miles, whichever comes first.
- Tuned road car: Service every 12 months or 10,000 miles, whichever comes first.
- Normal road use: A suitable 5W-20 engine oil remains appropriate for standard and tuned ST250s.
- Hard road or track use: A suitable 5W-30 or 5W-40 may be considered depending on how the car is used.
- Standard spark plugs: Replace every two years.
- Tuned-car spark plugs: Replace every year.
- Air and cabin filters: Replace every two years.
- Manual gearbox oil: Replace approximately every three years.
Ford Focus ST250 service intervals
Ford’s standard service interval for the MK3 Focus is every 12 months or 12,500 miles, whichever comes first.
For a standard road car, this remains a suitable maximum interval when the car is maintained correctly and used normally.
For a remapped or otherwise tuned Focus ST250, we recommend reducing the mileage interval to:
- 12 months or 10,000 miles, whichever comes first.
A tuned engine may spend more time under increased load and boost, so reducing the mileage between oil and filter changes provides a sensible additional margin without creating an unnecessarily demanding maintenance schedule.
What is included in the Focus ST250 service kit?
Our Genuine Ford Focus ST250 service kit provides the main components required for a routine engine service.
The base kit includes:
- 6 litres of Castrol 5W-20 engine oil
- Genuine Ford engine-oil filter
- Genuine Ford sump plug
Depending on the selected options, the kit can also include:
- Genuine Ford spark plugs
- Genuine Ford engine-air filter
- Genuine Ford cabin filter
This makes it suitable for routine maintenance on standard, Stage 1 and Stage 2 Focus ST250 models.
What engine oil should be used in a Focus ST250?
Normal road use
A suitable 5W-20 engine oil is absolutely fine for both standard and tuned ST250 road cars.
Simply having a Stage 1 or Stage 2 remap does not automatically mean that a substantially thicker oil is required. For ordinary road temperatures and normal driving, the correct 5W-20 provides suitable lubrication and cold-start performance.
Hard road and track use
For cars driven particularly hard, used repeatedly at high oil temperatures or taken on track, a slightly thicker oil may be appropriate.
Depending on the car, conditions and intended use, this may mean switching to a suitable:
- 5W-30
- 5W-40 in some applications
Oil choice should be based on how the car is actually used rather than power output alone. Contact us before changing specification if you are unsure what is appropriate for your setup.
Which spark plugs should be used in a Focus ST250?
Standard Focus ST250
For a standard car, the original-specification Genuine Ford ST250 spark plugs are the straightforward replacement choice.
They retain the standard Ford specification and are suitable for an unmodified road car.
Stage 1 and Stage 2 Focus ST250
For Stage 1 and Stage 2 cars, we recommend either:
The Focus RS plugs are a popular OEM-style upgrade for the ST250. The uprated NGK plugs are one heat range colder and are a suitable alternative for tuned applications.
For the NGK plugs, we recommend checking and setting the plug gap to approximately 0.65 mm before installation.
How often should ST250 spark plugs be changed?
Our recommended intervals are:
- Standard car: Replace the spark plugs every two years.
- Tuned car: Replace the spark plugs every year.
Tuned EcoBoost engines are more sensitive to plug condition and gap. Worn plugs can contribute to misfires under load, hesitation and inconsistent performance, even if the car still drives normally during gentle use.
Focus ST250 coil-pack problems
Ignition coil packs can begin breaking down as the car ages. A weak coil may cause:
- Misfires under boost or heavy acceleration
- Hesitation at higher engine load
- Rough running
- An engine-management light
Misfires should be properly diagnosed rather than assuming that the spark plugs are always responsible. Plug condition, plug gap, coil packs, wiring and fuelling can all produce similar symptoms.
Air-filter and cabin-filter intervals
For normal road use, we recommend replacing both the engine-air filter and cabin filter approximately every two years.
The engine-air filter should be inspected sooner if the car is used in dusty conditions or covers unusually high mileage. A heavily contaminated filter can restrict airflow and should not be left in place purely because it has not reached the suggested time interval.
The cabin filter does not affect engine performance, but replacing it helps maintain airflow through the heating and air-conditioning system.
How often should Focus ST250 gearbox oil be changed?
We recommend replacing the manual gearbox oil approximately every three years.
Although gearbox oil is sometimes treated as a very long-life fluid, regular replacement is sensible on a performance car, particularly where it is driven hard or produces more torque than standard.
Our Genuine Ford Focus ST250 gearbox oil is supplied in one-litre bottles. Two bottles are required for a gearbox-oil change.
Does the Focus ST250 have a cambelt or timing chain?
The 2.0-litre EcoBoost engine uses a timing chain rather than a conventional scheduled-replacement cambelt.
There is no need to replace the timing chain routinely when it remains quiet and the engine is operating correctly. Timing-chain problems are rare on these engines.
If an abnormal chain rattle or other mechanical noise develops, it should be investigated rather than automatically replacing components based solely on the age or mileage of the car.
Focus ST250 lambda sensors
The Focus ST250 uses separate oxygen sensors before and after the catalytic converter.
Front lambda sensor
The front Bosch lambda sensor is positioned before the catalytic converter and is involved in monitoring the engine’s air-fuel mixture.
A faulty front lambda sensor will normally illuminate the engine-management light and store a relevant fault code.
Rear lambda sensor
The rear Bosch lambda sensor is the post-catalyst sensor.
Lambda sensors should be treated as diagnostic replacement parts rather than routine service items. The car should be scanned and the fault properly diagnosed before a sensor is ordered, as wiring faults, exhaust leaks and catalytic-converter issues can sometimes produce similar fault codes.
Focus ST250 service-part fitment
The relevant service parts in this collection are the same across:
- Pre-facelift Focus ST250 models
- Facelift Focus ST250 models
- Hatchback models
- Estate models
Customers should still check the individual product description or contact us with their registration if they are unsure about a particular component.
Frequently asked questions
How often should a standard Focus ST250 be serviced?
Every 12 months or 12,500 miles, whichever comes first.
How often should a tuned Focus ST250 be serviced?
We recommend every 12 months or 10,000 miles, whichever comes first.
Is 5W-20 oil suitable for a remapped ST250?
Yes. A suitable 5W-20 remains appropriate for a tuned road car. A thicker oil may be considered for repeated hard use or track driving.
Should I use 5W-30 or 5W-40 on track?
A suitable 5W-30 or, in some cases, 5W-40 may be appropriate for sustained high-temperature use. The best choice depends on the car and how it is being driven.
Which spark plugs are best for a standard ST250?
Use the standard Genuine Ford ST250 spark plugs.
Which spark plugs are best for Stage 1 or Stage 2?
We recommend either Genuine Ford Focus RS spark plugs or NGK one-step-colder plugs.
What gap should be used with the NGK uprated plugs?
We recommend checking and setting them to approximately 0.65 mm.
How often should tuned-car spark plugs be replaced?
We recommend replacing them yearly on a tuned Focus ST250.
Can worn coil packs cause a misfire under boost?
Yes. Coil packs commonly deteriorate with age and can cause misfires or hesitation when the engine is placed under higher load.
Does the ST250 timing chain need scheduled replacement?
No. It does not need routine replacement unless it becomes noisy or a fault is diagnosed, which is relatively rare.
How much gearbox oil is required?
Two litres are required, so order two of the one-litre Genuine Ford bottles.
Should lambda sensors be replaced as routine maintenance?
No. They should normally be replaced only after proper diagnosis confirms that the sensor is faulty.
More Focus ST250 parts and tuning advice
Browse our complete range of MK3 Ford Focus ST250 performance parts, or read our Focus ST250 tuning guide for advice on Stage 1, Stage 2 and supporting modifications.
Vendor:Genuine Ford
Vendor:Genuine Ford
Vendor:Bosch
Vendor:NGK
Vendor:Genuine Ford
Vendor:Bosch
