Lexus ES/RX: How to Replace Spark Plugs
Replacing the spark plugs in a Lexus ES or RX is a task that can be performed at home by those with patience and a good set of wrenches.
This article applies to the Lexus ES and RX (2007-2014).
The spark plugs are key to a well running engine. Over time, the plugs will provide less spark as wear progresses.
This repair is made difficult by the three spark plugs that are on the back side of the engine. You will be removing the intake plenum as well as many electrical and hose connections. This repair should only be done by those with experience. It is highly suggested that you watch the featured video below prior to considering doing this task yourself.
Materials Needed
- Metric 3/8" drive socket set; specialty, 10 mm, 1, mm, 14 mm, and 19 mm
- 3/8" drive universal joint
- 5/8" spark plug socket
- Flex head ratchet wrenches
Pro Tip
Replacing the front three spark plugs are easy, but for this tutorial, it is recommended to start with the rear spark plugs. Most of the work is in removing the vacuum hoses and intake plenum so that the rear plugs are accessible.
Step 1 - Remove the strut brace and engine cover
Remove the two bolts at the end of the strut brace and remove the brace. Remove the bolts at the front of the cover. Lift the cover from the front then pull it towards you to free the tabs from the holding brackets.
Figure 1. Unbolt the strut brace from the shock towers and remove. 
Figure 2. Remove the three bolts at the front of the engine cover to remove it.
Step 2 - Remove vacuum hoses and intake
Remove the bolts that hold the air box and any hoses. Remove the top of the air box and slide the hose off of the throttle body.
Figure 3. View of the engine with the air box and strut support attached. 
Figure 4. View of the engine with the air box and strut support removed.
Step 3 - Remove fuel rail and intake plenum
Unbolt the intake plenum from the head. There are 14mm bolts at either end. Also remove the 10 mm bolt and four hex head Allen bolts. Unbolt the intake plenum from the bracket. There are two 12mm bolts on the driver's side and a 14mm bolt on the passenger side. Remove the bolts with the flex head ratchet wrenches or sockets with a universal joint.
Figure 5a. Remove these bolts securing the intake to the head. 
Figure 5b. Remove the bolts shown in order to remove the intake plenum. 
Figure 5c. These back bolts that go into the brackets are very hard to see.
Pro Tips
- Seal the intake ports by covering them with masking tape to keep objects from falling into the engine.
- Change the PCV valve that’s under the intake plenum while you have everything apart. Use a 19 mm wrench. Also clean the throttle body while it is out of the car.
Step 4 - Replace spark plugs
Remove the ignition coils from the spark plugs using a 10 mm socket. Pull the coil and spark plug boot assembly from the spark plug. While the ignition coil is out, examine the spark plug well for oil and other fluids. Often time a leaky valve cover gasket will allow oil to seep into the plug area. Use a 5/8" socket and 6 " extension to remove the spark plug. Gap new plug to specs, place in socket and screw into engine, torquing down to 25 N*m (254 kgf*cm or 18 ft*lbf).
Figure 6a. Removal of coil. 
Figure 6b. With coil removed, spark plug is now accessible. 
Figure 6c. After hand-tightening the spark plug, use a torque wrench to finish.
Pro Tips
- Place a little bit of motor oil on the plug threads before installing. If you use anti-seize compound on the threads, apply it sparingly and keep away from the plug's electrode and lower threads. If it gets on the electrode it will shorten the life of the plug considerably.
- Tape your spark plug socket to your extension to keep the socket from falling off.
Step 5 - Reassemble in the reverse order
Install the coils. Slide the spark plug boot over the plug and push it firmly on until you feel it seat properly. Bolt the coil down and connect the electrical plug. Install the fuel rail. Bolt the rail in place. Reconnect all electrical plugs and hoses. Install the two 12mm throttle body bolts. Install the air box and all hoses and connections. Install the engine cover. Install the strut support.
Pro Tip
Tie fishing line around bolts in case you drop them behind the engine where space is limited.
Featured Video: Lexus ES Spark Plug Replacement
Related Discussion
- Lexus ES and RX Spark Plug Replacement - ClubLexus.com
