Bullochdaw

Had a "Check Engine" light come on and showed misfire on #7 and was running rough. Decided to change all eight plugs and coils as it was way overdue.
Changed those Saturday and CE light went off and everything ran smooth again.
This morning the CE light was back on and it was running rough again.
I did notice oil around the plugs and coils when replacing and thought it was just residual.
Now I'm thinking not so much.
Going to tackle replacing the valve cover gaskets (unless there are other suggestions). Have seen a few threads on this and they usually come with "While you're in there, you might as well replace ____" type comments.

I'm a medium skill level mechanic. I usually watch a few Youtube videos and make the determination of if something is within my skill level based on what I see. Haven't watched any videos on gasket replacement yet, since this just happened on the way to work.

From replacing the plugs and coils, it doesn't seem "that" difficult to replace the valve cover gaskets. Am I right, or getting in over my head?

My LS430 has 250k on it. I'm the second owner, so not sure what was replaced before I got it. I'm going with the assumption of Nothing.

So, what other "stuff" should I replace while I'm in there?

TIA

911LE

If you are getting oil around your plugs make sure you replace your spark plugs tube seals as well. They are installed on the underside of the valve covers. To replace each one you just bend the 4 metal tabs straight up and pry the seal out with a large screwdriver. You can tap the new ones into place with a hammer and large socket. When reinstalling the valve covers with their new gaskets make sure you put a dab of silicone where the front bearing cap meets the cylinder head (the spot where the gasket makes a 90 degree turn, 2 per cover) and in the back where the 2 half moon aluminum pieces meet the head as well (4 spots total each head ). If those pieces are loose or it looks like oil was leaking around them you can pull them out, clean them and the head, and reinstall with a bead of silicone around the outside.

Bullochdaw

Should I replace the coils again as well?
Should I just put a bead of silicone all around the gasket, or just the places you mentioned?

Thanks for the info!

911LE

Your coils and plugs should be fine. I was saying you need to replace the spark plug tube seals. I don't think they come with the new valve cover gaskets. Only put the silicone where I said, you don't need it anywhere else and it will make a mess.

Legender

PCV grommet, hose and valve should also be replaced at this time.
The second time the light came on I assume it was the same code?

lorenr

iTrader: (1)

Your original coils were probably fine as well. Hopefully you saved them. Should not replace coils unless you get that code.

When you pulled the plugs, the oil in the plug well simply ran down into the combustion chamber. Next time check the plugs. If they are wet, then that plug seal is leaking. Most engines of this design eventually have the seals and valve cover gaskets go bad. Even though these Toyota seals are pretty good, heat will cause them to go bad. Probably gets real warm in Georgia.

I'm curious also. What code did you get?

Bullochdaw

Thankfully, I got busy and never changed the gaskets....because that's not the problem...at least not now.
Originally I had a #7 misfire that led me to change the plugs and coils in the first place. That fixed it for awhile. When the Check Engine light came back on and it was running rough, I assumed it was the same problem (same symptoms) again. It has been leaking oil - somewhere - as I have to add a qt. every 4th or 5th fill up, and I can smell burning oil. So, all that led me to believe it was the valve cover gaskets(s). That and the oil on all of the plugs. Plus I saw oil around the cover (that may be from it being under the oil filler). It may still be a problem, but...

Got my code reader back from a friend and pulled a P0330 - Knock Sensor 2.

I reset the code and it's running fine with no CE light. I'm sure it will come back. So, now I'm looking at replacing the Knock Sensor(s).

I still have an oil leak somewhere, but that's for another day.

Thanks for the input and suggestions. I know better than to make assumptions. Could've been a costly assumption.

911LE

If you can smell burning oil from the engine compartment chances are it's your valve covers. Your knock sensors are located under the intake manifold. Not too hard of a diy. Any questions let me know as I just had the entire top end of my engine off down to the block. I'm quite familiar with all that is involved.