Ford Spark Plug | Ignition Coil Replacement | 4-Cylinder Engine
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Is your Ford engine misfiring, its check engine light is on, a rough idle, and its power decreased? Learn how to fix the problem by replacing your Ford’s spark plug. The four-cylinder engine is found on Ford S-Max, Ford C-Max Mk I, Ford Mondeo Mk III, Mk IV, Ford Focus Mk II, and also on Mazda 3, Mazda 5, Mazda 6, Ford Galaxy Mk III.
What you will need
- Ford Spark Plugs
- Ford Ignition Coils (optional)
- Spark Plug Socket
- 3/8″ Ratchet wrench
- 3/8″ 6-inch extension
- Torque Wrench
- Anti-seize (only if your service manual calls for it)
- Metric sockets
- Magnetic Pickup tool (optional)
Procedure
- Park the vehicle and allow the engine to cool down. Remember to set the parking brake. Pull the hood release and open the hood.
- Remove the engine cover.
- Unplug all the electrical connectors from the ignition coils.
- Remove the 10 mm bolts that hold the ignition coils. Remove the ignition coils by pulling them up.
Use a spark plug socket, extension, and ratchet to remove the spark plugs.
Install the new spark plugs. Carefully lower them into the engine. Don’t allow them to drop because the spark plug’s gap may be affected. Torque the spark plugs to specification.
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Install the ignition coils and electrical connectors.
Reinstall the engine cover.
Start the vehicle and check to ensure the engine is running smoothly.
Torque Specifications
The torque for spark plugs varies depending on the spark plug thread size and gasket type.
Typical values:
- 14 mm spark plugs: 8 to 15 lb. ft.
- 18 mm spark plugs: 15 to 20 lb. ft.
Tightening spark plugs with a torque wrench is recommended. If installing spark plugs without a torque wrench, tighten them until they are snug tight, plus an extra 1/8 to 1/4 turn.
Symptoms
- Check engine light on
- Car overheats
- Reduced power
- High fuel consumption
- Engine shakes
- Engine runs rough
Spark Plug Gap
Ford spark plug gap can range from 0.036″ to 0.050″.
A new spark plug should be pre-gaped for your engine. Verify the correct spark plug gap by looking it up in your owner’s manual or calling your Ford or Mazda dealer parts department.
Do not gap the new spark plugs based on the gap of the old spark plugs. The old plugs will have a bigger gap due to spark plug wear.
Spark Plug Replacement Interval
The spark plug replacement interval directly correlates to the type of spark plug installed on your car.
Typical spark plug replacement intervals:
- Copper: 30,000 to 50,000 miles
- Platinum: 60,000 to 100,000 miles
- Iridium: 100,000 to 120,000 miles
Check Engine Light Still On
If the check engine light is still on when you have replaced your vehicle’s ignition coil and spark plugs, you can use the YOUCANIC Full System Scanner to clear the codes. This scanner can also read and clear fault codes through every control module of your vehicle, if it is supported.
Check these troubleshooting and repair guides for more help on your Ford.
