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Autopapyrus · Chevrolet Onix 1.2 (90 hp) (2023)
https://autopapyrus.com/guides/chevrolet/onix/spark-plug-replacement/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Chevrolet Onix 1.2 (90 hp) (2023): Spark Plug Replacement

The 1.2 is a three-cylinder engine with individual ignition coils mounted directly on the spark plugs. You reach the plugs after removing the decorative cover and the coils. The replacement interval is usually 30,000-60,000 km depending on the electrode type. The exact procedure for this model is not documented in publicly available service materials, so what follows is the general approach for engines with coil-on-plug ignition. Check the gap and torque values against the manufacturer's specifications.

Difficulty: Easy Time: 30-60 minutes Steps: 13 Tools: 16 mm spark plug socket with a rubber insert or magnet (confirm the size against the plug you remove), extension, ratchet, torque wrench, Torx bit or 10 mm socket for the coil mounting bolts (as equipped), compressed air or a blow-out tool, dielectric grease for the coil boots

Part

  • 🔩 Spark plug set for the 1.2 (3 cylinders). The engine manufacturer specifies the plug type and gap, so buy plugs with the same designation as the ones you remove, or genuine Chevrolet plugs listed in the catalog for this engine. Brands include NGK, Denso, Bosch and OE

Step by step

13 steps
  1. Work on a cold engine. Shut the engine off and let it cool for at least 1-2 hours. The threads in an aluminum cylinder head are easily damaged when the engine is hot.
  2. Disconnect the negative battery terminal if you plan to unplug the coil connectors. This is not required, but it is safer.
  3. Remove the decorative plastic engine cover, if fitted. It is usually held on by clips or a few screws.
  4. Press the locking tab and disconnect the electrical connector from each coil. Do not pull on the wires.
  5. Remove the coil mounting bolt (usually one bolt per coil). Gently rock the coil and pull it straight up and out. Do not pry it with a screwdriver.
  6. Blow out the spark plug wells with compressed air so dirt does not fall into the cylinder when you remove the plugs.
  7. Remove the plug with the socket that has the rubber insert, keeping it exactly in line with the plug, with no tilt. If the plug is tight, first apply penetrating oil and wait 10-15 minutes.
  8. Inspect the old plugs. A light gray deposit on the electrodes is normal. Black soot, oil or melted electrodes point to a problem: a rich mixture, oil leaking past the valves, or overheating.
  9. Check the gap of the new plugs with a feeler gauge (if the plugs do not come pre-gapped) and compare it with the manufacturer's specification. Do not bend the side electrode on iridium and platinum plugs, because they are sensitive to this.
  10. Thread the new plug in by hand until it seats, so you do not strip the threads. Do not lubricate the threads or use copper anti-seize unless the plug manufacturer calls for it.
  11. Tighten with a torque wrench. For M12 or M14 plugs with a tapered or flat seat, the usual range is 18-30 N·m (13-22 lb-ft). Use the exact value from the manufacturer's specifications and the data on the plug packaging.
  12. Apply a thin layer of dielectric grease to the rubber boot of each coil. Install the coils until they click into place, tighten the mounting bolts without excessive force, and reconnect the connectors.
  13. Refit the engine cover and the battery terminal, then start the engine. It should run smoothly, without misfiring. Check that no warning lights appear on the instrument cluster.

Common mistakes and warnings

  • Replace the spark plugs as a complete set, not one at a time. Uneven wear is especially noticeable on a three-cylinder engine. Do not overtighten the plugs: stripping the threads in the aluminum head leads to an expensive repair. If a misfire appears after the replacement, the Check Engine light comes on, or a coil connector did not latch, check that the coils and connectors are fully seated. If the problem persists, take the car to a repair shop for diagnosis.