How to properly replace automotive spark plugs?

1. Prepare tools and materials
Confirm the model of automotive spark plugs according to the model manual, including thread size, calorific value and material. Do not mix spark plugs of different materials or calorific values. Prepare spark plug sockets (with magnetic or rubber ring to prevent falling off), torque wrench (recommended 20-30N·m), ratchet wrench, ignition coil puller. Gloves, dustproof cloth, high-voltage insulating silicone grease, white vinegar (clean old spark plugs).

2. Replacement steps
After opening the engine compartment, disconnect the negative pole of the battery and wrap it with insulating cloth to prevent short circuit or accidental contact. Use compressed air or a brush to clean the dust around the spark plug to prevent foreign matter from falling into the combustion chamber. When removing the old spark plug, loosen the fixing screw with a screwdriver and pull out the ignition coil vertically. If the coil is stuck, it can be pulled out by gently shaking to avoid violent damage to the plug. Remove the old spark plug with a magnetic rod or rubber tube and check the carbon deposits. When installing a new spark plug, wipe the new spark plug thread with a lint-free cloth, and apply a small amount of high-voltage insulating silicone grease to the contact point of the ignition coil to enhance the sealing. Put the new spark plug into the sleeve, insert it vertically into the cylinder, and turn it clockwise by hand until it cannot turn.

3. Precautions when replacing
When removing the spark plug, cover the open cylinder port with a dustproof cloth to prevent dust, screws, etc. from falling into the combustion chamber. If the cylinder head is made of aluminum alloy, excessive tightening may cause the threads to slip, and the torque must be strictly followed. It is safer to replace the cold car. The expansion of the cylinder body during hot car may make it difficult to remove the spark plug or damage the thread. Multi-cylinder engines need to mark the order of the ignition coil harness to avoid ignition confusion caused by incorrect installation.