Toyota Camry (97-01 4-Cylinder 5SFE) Spark Plug Replacement
Tips Before You Get Started
When you replace the spark plugs on your Camry, I recommend replacing them with iridium plugs as a simple and safe way to enhance performance: see the discussion at the end of this article.
Clean the PCV Valve
At the same time you replace the plugs, either clean or replace the PCV (Positive Crankcase Ventilation) valve, which is located on the valve cover between the number 2 and 3 ignition wires. The PCV valve channels unburned carbon blow-by gases back into your combustion chamber. A valve stuck closed will allow these gases to react with the motor oil and possibly cause the formation of engine oil sludge, a subject that was controversial for Toyota in the late '90s. In addition, a PCV valve stuck closed will create internal engine pressures that can cause oil to leak through the crankshaft, camshaft, and/or oil pump seals, requiring their replacement.
Track Down Valve Cover Leaks
When you pull the ignition wires to gain access to the plugs, you will see a valve cover locking nut for each spark plug hole. These nuts have a tendency to loosen, allowing oil to leak from the back side of the valve cover. In very bad cases, oil will leak from behind the front passenger side wheel. Re-tightening these nuts will eliminate the leakage. If an oil leak continues to this area after tightening up the valve cover nuts, the leak may be coming from:
- a worn crankshaft, camshaft or oil pump seal, or
- a worn oil pump rubber gasket.
The procedures for replacing these parts can be found in my article on timing belt replacement.
I. Removing the Spark Plugs
a. Spray the ignition wire clips with silicone spray and detach wires from the clips. If you do this without lubrication, you run the risk of breaking the clip off of the valve cover.
b. Detach the right-most driver's side ignition wire from the coil pack; otherwise there will not be enough wire length to remove the wire from the spark plug tube.
c. Pinch, twist and pull up on the rubber ignition wire nipple above the rectangular cap to detach the wire from the plug. If this proves difficult, pinch and pull with long-nose needle-nose pliers using the base of the valve cover for leverage. *WARNING - Regardless of how careful you are removing the wires, you run the risk of damaging the wire if the wire does not detach easily from the plug. It could be stuck due to the ignition wire's rubber boot fusing to the plug's ceramic insulator. Use silicone or di-electric grease on the boots during re-installation.
d. Remove the plugs using a 3/8 socket wrench attached to a 4" extension and 5/8" spark plug socket. If the plugs seem frozen in place, spray penetrating oil into the plug hole and let the oil saturate the threads. Combine loosening and tightening action to allow the oil to migrate.
II. PCV Valve Removal and Cleaning
a. Using long-nose needle-nose pliers, position the plier tips under the lip of the PCV base and use the valve cover as a leverage base to pull up on the valve.
b. Position the PCV hose clamp away from the PCV outlet and twist off the valve from the hose.
c. Shake the PCV valve. If it is relatively free of carbon, you can hear the spring inside when you shake it. Either way, spray Carb Cleaner into both openings of the valve, seal the openings with your thumb and index finger, then shake the valve. Keep shaking until the internal spring and plunger move freely. Drain out the Carb Cleaner.
d. Reverse above steps for re-installation.
III. Tighten the Valve Cover Locking Nuts
a. Use a 30mm 1/2" socket.
b. Alternate the tightening sequence from the inside out. That is: plug holes 3, 1, 2, 4, in that order. Do not completely tighten each nut. Gradually spread out the tension.
IV. Install the New Spark Plugs
a. If the threads in the cylinder head seem corroded, use a thread-chasing tool to clean them up.
b. Use anti-seize lubricant on the spark plug threads to prevent plug seizure for the next change.
c. Don't use a 1/2" socket wrench to install the new plugs. A 3/8" provides just about the right amount of torque for a tight spark plug fit. If you aren't sure about the proper amount of tension, use a 3/8" torque wrench.
d. Lubricate the tips and the interior caps of the ignition wires with silicone or di-electric grease to ease installation and future removal.
e. Carefully attach the ignition wire clips. Too much pressure will snap the clip off the valve cover.
Try Iridium Plugs
To keep your Camry in top-notch running condition, consider replacing the standard factory double-electrode spark plugs with iridium plugs. Iridiums generate a bigger spark, last just as long as platinum plugs, and are now the auto industry standard on new vehicles. It's the simplest and cheapest performance enhancement you can make to improve fuel economy and power.
Denso and NGK were the first to provide these plugs, which were very expensive when first introduced over 10 years ago. Now Champion, Autolite, and Bosch provide their own versions at competitive prices. The standard center electrode diameter is 0.6 mm; Denso is the only company with a 0.4 mm plug, which produces a hotter spark but sacrifices longevity. Iridiums work extremely well in forced-induction turbo applications where air and fuel are "rammed" into a combustion chamber, a process requiring high-quality plugs for complete and efficient combustion.
Although some will refuse to deviate from the manufacturer's stated spark plug brand and type, iridium plugs have been thoroughly tested by the auto industry and are standard on many new car applications. Replacing the obsolete spark plug design with new-state-of-the-art Iridiums will not harm the engine in any way.