How to change spark plugs in Lexus GS300

The spark plugs in your Lexus GS300 complete the compression process that keeps the engine running. As fuel and oxygen enter the cylinders, the piston rises and at the top of its stroke, the spark plug ignites the mixture. As a result of the explosion, the piston goes down. If the spark plug fails to transfer electrical charge to the cylinder, the car will misfire and the engine will splatter. Spark plugs are not difficult to replace. You can finish a project in about an hour.

Step 1

Measure the gap for each new spark plug with a feeler gauge. The "gap" is the space between the filament and the flash point at the top of the spark plug. Measure the clearance between the actuation point and the thread using a suitable blade on a feeler gauge. In this case, the Lexus candle gap should be 0,044 thousandths. Spark plugs are installed from the factory, but you should still check each one.

Step 2

Disconnect the spark plug wire from the spark plug, holding the cap as close to the engine as possible, and carefully pull it away from the spark plug. Remove the spark plug from the cylinder head with a spark plug and ratchet and discard it.

Insert a new plug into the GS300 cylinder head. Tighten it with a ratchet and a spark plug. Be careful not to twist the spark plug or you will damage the cylinder head. Insert the spark plug wire back into the spark plug. Repeat the process on the next plugin.

Tip

Inspect the spark plug wires when replacing each of the spark plugs. If there are any signs of damage, the entire set of cables should be replaced.

A warning

Do not overtighten the spark plugs or you will damage the spark plug and possibly the cylinder head.

Items you will need

• Spark plug
• ratchet
• Thickness measurement