Mechanics

CHANGING SPARK PLUGS

2002 Toyota Sienna

Engine Performance problem
2002 Toyota Sienna 6 cyl Front Wheel Drive Automatic 170000 miles

How do I change the rear 3 spark plugs? Can you tell me how a novice could do it.
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Dmetalman
November 6, 2010.




Pop the hood, and remove the plastic engine cover. I assume you know how to remove the front plugs. So I'll only focus on the rear plugs.
Start on the right side. Unclip some of the vacuum hoses and spread them out to the sides of the opening. You should see a hole that extends back underneath the air intake and next to the exhaust manifold. Reach back there with your arm. Feel for a 1 inch square block and securing hex bolt. Using feel only, use the 10mm closed-end box wrench and loosen the securing nut. A hard counterclockwise tweak should break it loose, and about a half dozen more small loosening motions should loosen the bolt so you can switch out and use your fingers. Remove the bolt and place it away from the engine in a safe place. Lift the boot assembly out. Watch to make sure the rubber grommet doesn't slide off and fall in the oblivion never to be found.
WithOUT the rachet driver, get the socket and extension and slide down tube, then reach in with rachet and unscrew the spark plug. Remove the rachet, and lift extension and spark plug out. If your socket doesn't grip the spark plug, take it out, wrap the lip with a little masking tape). Installation is the reverse of removal.
Get a new spark plug. Slide it inside the spark plug socket and make sure it grips but not too tightly. The plugs are pre-gapped at the factory and have a plastic sleeve to protect the head. You must NOT allow the plug to drop down the tube because the impact could bend the tip and affect the gap or damage the plug.
There are two metal compression washers on the spark plug. There's no room for a torque wrench back there, so tighten the plugs down until the compression washers just begin to feel like bottoming out. Then twist another 30 deg. Do NOT slide the boot/coil assembly back over the spark plug yet. The first boot must remain out from its tube to allow the second boot room for removal.
The middle boot assembly is a bit harder. It's just like the first, but you need to disconnect the wire harness clip to each boot/ignition coil. With a single hand, rock the boot assembly a little until it lifts up and off the plug about 1 inch. Then turn the boot assembly clockwise a little and use the technique you practiced to unclip the wiring harness from the boot assembly. There is only room for one hand in there. Be persistent and follow technique and practice. Eventually, you should be able to get the wire clip off.
Now the boot/coil should lift out easily. Then use the spark plug socket and reach back in there and slide the socket down the tube and then attach the rachet driver and remove the spark plug. Installation the reverse of removal. Again, be careful about dropping any parts down into the engine.
The 3rd boot is like the 2nd, because you need to disconnect the wiring clip, but it's different in that instead of reaching in from the right side, most of the extraction uses the opening from the left side.



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