Valve Cover Gasket Replacement and Tune-Up on a Lexus ES 300 or '04-'00 Camry V6 (With Videos)

Updated on January 16, 2019
hardlymoving profile image

Hardlymoving writes about do-it-yourself automobile maintenance on various makes and models.

The Lexus ES300 is a marvelous car to own and drive. Although it has the same transmission and suspension as the Toyota Avalon and Camry, the ES 300 comes with higher-quality exterior paint, better interior materials, and superior sound-deadening attributes. It's very comfortable to drive on long trips. Because many of the mechanical parts in the ES300 are interchangeable with the Camry and Avalon, parts are inexpensive and easy to come by.

Before the project in the video below, I had helped two of my friends purchase and maintain '98 and '99 ES300s. Both cars are approaching the 200,000-mile mark now, but both owners love their cars so much they would not consider selling them.

My ES 300 Restoration Project

The 1997 ES300 in the video below had 165,000 miles on it when I bought it. The car had been sitting idle in a garage for two years with a stuck-open sunroof, a broken driver's-side door handle, and an engine that would not start (seized water pump and timing belt bearings). The owner had recently purchased an ES 350 and did not want to invest in his ES300 to make it operational.

To get the car back on the road, I replaced the water pump and timing belt components at the owner's garage. After that, I performed the tune-up in the videos below to get the car running like new.

Elements of This Tuneup

These videos show you what I did:

  • Replaced the valve cover gaskets
  • Replaced the spark plugs
  • Replaced the ignition wires
  • Removed and cleaned the throttle body
  • Replaced an upstream oxygen sensor on the firewall side of the exhaust manifold

I had to replace the valve cover gaskets because they were leaking. The most difficult and timing consuming part of that job is getting to and removing the right bank valve cover gasket. The right bank is up against the firewall and is covered by both a wire harness and the intake plenum. Since so much effort goes into removing the intake plenum, once it's removed and exposes the spark plugs, it is worth replacing the spark plugs at the same time since they are normal wear items. Also, I thought the ignition wires were worth replacing due to the car's age and mileage. I cleaned the throttle body because I know EGR gases accumulate carbon on the throttle plate causing it to stick. I replaced an upstream oxygen sensor on the firewall side of the exhaust manifold because an MIL (malfunction indicator lamp) lamp was on.

My Lexus ES 300 after the tuneup.  Note the intake manifold in back against the firewall; you have to remove a lot of things to get to the firewall-side valve cover.
My Lexus ES 300 after the tuneup. Note the intake manifold in back against the firewall; you have to remove a lot of things to get to the firewall-side valve cover. | Source

Step By Step: Tune-Up of a Lexus ES 300

The videos below show you step-by-step how to access the valve cover gaskets, remove and clean the throttle body, replace the spark plugs and ignition wires, and replace the 02 sensor.

1. Remove the Air Filter Top Cover and Air Hose

The video below will walk you through removing the air filter top cover and the air box hose attached to the throttle body.

Air Filter Cover and Hose Removal Video

2. Remove the Throttle Body

After you remove the air hose, the video below will walk you through removing the throttle body. The only difficult part of this procedure is disconnecting the three hoses attached to the bottom of the throttle body. You can use bent needle-nose pliers to pinch the hose clamps, and needle-nose hose clamp pliers to twist the hose off. Afterwards, you can apply paint marks to the hoses if you're concerned the hoses may get mixed up during re-attachment.

Throttle Body Removal Video

3. Clean the Throttle Body

After you remove the throttle body, I highly recommend you clean it, to get rid of carbon and varnish buildup deposited by EGR gases. The buildup can cause the throttle plate to stick; a stuck throttle plate can result in sudden acceleration when the plate springs open when you depress the gas pedal. Use a combination of carburetor spray cleaner and a plastic or brass wire brush.

The video below will show you how I did it.

Throttle Body Cleaning Video

4. Remove the EGR (Exhaust Gas Recirculation) Valve

After you remove and clean the throttle body, you have to remove the EGR valve as well in order to removed the intake plenum. After the EGR has been removed, you can use a tube wire brush to clean off any carbon debris inside the input and output ports of the EGR.

The video below will show you how I did it.

EGR Removal Video

5. Remove the Intake Plenum

After you have removed the EGR valve, throttle body and the air intake hose, you can remove the intake plenum. The most difficult task is unbolting the nut that holds the plenum bracket onto the plenum, right up against the firewall. A 14-mm socket attached to a 1/4 inch socket wrench gives you just enough clearance to fit the socket and wrench between the bracket and firewall.

The video below will show you how I did it.

Intake Plenum Removal Video

6. Lift the Electrical Harness Away From the Firewall Side Valve Cover

After removing the intake plenum, unbolt the electrical harness and lift it away from the firewall-side valve cover.

The video below will show you how.

Lifting the Electrical Harness Away From the Valve Cover Video

7. Remove the Firewall-Side Valve Cover

After lifting the electrical harness above the valve cover, you can now remove the firewall-side valve cover.

The video below will show you how.

Firewall Side Valve Cover Removal Video

8. Optional: Rear Oxygen Sensor Replacement (P0135 - Bank 1 Sensor 1)

The oxygen sensor by the firewall side required replacement. Since the intake plenum and valve cover were off, we were able to replace the oxygen sensor from the top of the engine compartment instead of from the bottom.

Rear Firewall-Side Oxygen Sensor Replacement Video

9. Reinstall the Valve Cover with the New Gasket (Firewall Side)

After mounting the new valve cover gasket onto the valve cover, you can bolt the cover onto the engine head. It is extremely important to use RTV sealant on the corners of the new gasket, where the gasket meets the hump of the camshaft, to ensure a leak-free seal. In addition, you need to torque on the valve cover bolts uniformly.

The video below will show you how.

Valve Cover Reinstallation (Firewall Side) Video

10. Replace the Spark Plugs

The video below will show you how to replace the firewall-side spark plugs. I did not use a standard spark plug socket to loosen the plugs but rather a 16 mm 3/8" long socket. Once the plugs are loose, I pull them out with a magnetic wand. When installing the new plugs, I apply a very light coat of anti-seize lubricant to the plug threads and torque the plugs down to 21-22 lbs with a torque wrench. I used to torque plugs down by feel, but now I use a torque wrench to ensure they won't come loose.

Spark Plug Replacement (Firewall Side) Video

11. Replace the Ignition Wires

If you're dealing with an old, high-mileage engine, it's a good idea to replace the ignition wires. The new wire set I had purchased had all the plastic connectors and wire separators attached to the wires like the original OEM wire set. This made the replacement extremely easy. I had previously purchased a wire set without the connectors and separators and had to transfer them all from the old wire set. It was a real pain.

The video below will show you how.

Ignition Wire Replacement Video

12. Reattach the Electrical Harness Over the Valve Cover

After re-installing the valve cover, re-attach the electrical harness that sits over the valve cover. The video below will show you how.

Electrical Harness Reattachment Video

13. Reinstall the Intake Plenum

The video below will show you how to reinstall the intake plenum.

Intake Plenum Reinstallation Video

14. Reattach the EGR

After you reattach the intake plenum, you can install the EGR valve.

The video below will show you how.

EGR Valve Reinstallation Video

15. Reinstall the Throttle Body

After the EGR, you can reinstall the throttle body.

The video below will show you how.

Throttle Body Re-installation Video

16. Replace the Front (Radiator-Side) Valve Cover Gasket and Spark Plugs

I like to reserve all the easy work for last. With the valve cover gasket, spark plugs, EGR valve, and throttle body being replaced or cleaned, the only thing left is replacement of the radiator-side valve cover gasket and spark plugs. Afterwards, we'll put in a new air filter and re-attach the airbox hose and cover.

The video below will show you how.

Radiator-Side Valve Cover Gasket and Spark Plug Replacement

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2018 hardlymoving


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    • hardlymoving profile imageAUTHOR


      15 months ago from Memphis, TN

      Glad you liked it!

    • profile image


      15 months ago

      Great work! Hard to find a mechanic who can be that thorough . Thanks for this video!!!


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