Saw this and looks like something is sticking out of front valve cover. It looked like grocery bag plastic at first but is probably thin rubber or silicone. Since oil is seeping my best guess is battered valve cover gasket.

I tried to inspect the rear valve cover but was not sure how to locate it. This may or may not be it (still not sure if there is a way to see it without removing obstacles), but i see something seeping there as well which leads me to think it's probably the rear cover.

 

Something strange sticking out next to the left of the bolt





Pic taken from bottom of vehicle

is this the rear valve cover?

 

That's just RTV squeezing out from the original install or a reinstall.

 

Derrick is correct

RTV is a sealant that is squeezed out from a tube in a paste form and once it dries and hardens goes to a rubbery state. it is placed between your valve cover gasket and the block to help seal the gasket , also it helps holding the gasket to the cover when installing .

From the looks of the pics you posted above it seems that your gaskets are leaking and need to be replaced as for the oil is leaking through them and running down your engine block. You have two valve covers in your lexus (Bank1 and bank 2)

Bank 2 is fairly simple to replace since its right in front of you when looking at the car from the front of the vehicle, but Bank 1 which is located closest to the fire wall will be a huge pain in the butt, expect 5-7 hours to replace if you never been that deep in your engine before , assuming you're doing the work yourself.

If you take it to a mechanic expect to pay anywhere around $500 for labor and $60 for parts

 

thanks guys. ideally i'd change them but i've been spending too much time working on this car as is. it's not leaking but seeping (no drips or puddles anywhere on the floor) and doesn't appear to require immediate attention. i've been thinking about changing the gaskets for some time now esp. since it's about time i change the spark plugs, but had i done it before i'd probably feel more comfortable attacking the rear. for now i'll continue to monitor it and will try to tighten the valve cover bolts when i get the chance.

 

The problem with an oil leak isn't really the oil loss or spots on the floor. The problem is that, over time, the oil will brake down any rubber it comes into contact with. Suspension mounts, boots and bushings will fail prematurely when soaked in oil. Wire harnesses and plugs will suffer as well. I've seen sections of wire harnesses completely stripped of insulation because someone ignored an oil leak.

 

Get ready for replace the valve cover gasket. If you remove the L sign engine cover you will be able to see rear valve cover too. You may jack up the car and see underneath the engine.

 

so i'll need to get the valve cover gaskets but do i need any other parts? i may/may not need other gaskets for the other parts i'm removing?

i know this job will take a long time, but what about the level of difficulty? i'm learning fast and eager to try, but obviously not at the expense of damaging the vehicle if something goes wrong or if i don't catch something that requires attention. so far i've done things like clean the iacv, brake job, and drop the transmission pan, so this is easily the most intimidating job. i really shouldn't be using this luxury vehicle as a guinea pig

 

I'm actually about to do this job myself and already have the parts here. Get a gasket set that comes with the spark plug tube seals. It's also a good time to replace the plugs since since you're already removing everything needed to access them. I'm also replacing the plenum (upper intake) gasket. I'm not sure how necessary it is on these but it's generally a good idea on this style of intake.

Also, make sure you have the torque spec for the valve cover bolts and plenum. Valve covers usually require a deceptively low torque and over torquing them can cause problems. they need to be torqued in a cross type pattern to compress the gasket evenly. I always go around several times before applying the final torque. The plenum bolts may also be a low torque.

I'm not sure what tools you have but a 1/4" flex head ratchet is great for this type of job. You shouldn't need anything bigger except for the plugs.

 

A few more general tips.

Get some cheap ZipLock bags. For every component you remove place the fasteners, clips etc in their own bag. label each bag with a marker and put them all in a small box. Even if it's one or two pieces. This has saved me many times. Both from using the wrong fastener AND from leaving one off. If you install a component and there's still a fastener in the bag you'll find where it goes right then. Otherwise, you might finish the job with a few parts left over. It's also harder for one bolt to disappear when they're organized.

Take a lot of high res pics with your phone along the way. There are always questions when going back together. Where does this plug go? Did this line route over or under this hose? Where did this vacuum line go? Etc....

 

so aside from valve cover just the upper plenum gasket? the other gaskets should be ok? looks like there a ton that come with manifold and plenum set. and also the throttle body ones.

i think i'll try the front one first and see how things go.

 

smack .. do you have service manual? You can get timed access .. details are in the sticky.

Salim

 

When I did this on my 99 RX with over 200K it was impossible for me to remove the spark plug tube seals - they were literally baked in place. My solution was that I installed a new rear valve cover that comes with spark plug tube seals pre-installed. I did not change the front; if they ever leak I will simply install a new valve cover.

 

i think i saw it but was confused if i was looking at the right part. i saw directions on inspecting that area but nothing termed "valve cover" or involving gaskets. i saw cylinder head which looked like the right section but as it was not a specific DIY i was not sure what to follow.