I just had the local dealer replace the valve cover gaskets on my 2001 LS430. A day later while rolling down I-80 at about 80-mph I felt the car hesitate, choke out a blue cloud of burnt oil and then it ran fine, until I started it again later that day. Then I noticed another large blue cloud of burnt oil. Now it appears I have an oil burning problem. I just turned 163,000 miles and figured I'd have the the valve cover gaskets replaced. The oil leak was only a small problem usually obvious just after an oil change for a week or so. But now after fixing the valve cover gasket leak I have a bigger and uglier problem of burning oil from the right bank of the engine. Any suggestions what the cause might be or even better, how does it get fixed? Thanks - JL

 

Sounds like they damaged something when the valve cover was off.

 

 

Might be valve guide seals going bad.if its not oil in the spark plug tubes.

 

I had no idea honestly I have not had the pleasure of doing the ls430 valvecover gaskets lol, I have done them on a bunch of other vehicles before with no problems is the LS just finicky or have I just gotten lucky with the other cars I have done?

Did the pinched spark plug tube seal give your car symptoms similiar to the op?

I immediately thought about the valve guide seals as well, as long as the op keeps adding oil he can prolong getting them replaced.

 

Take it back to the dealer and have them re-do the job. Simple. Ask them to have it done by an experienced technician, not an first year tech, just because your Lexus is old.

 

when i changed mine I had to be real careful with the gaskets, spark plug tube seals etc. I made sure everything was clean. it is a finicky job to say the least. I also replaced my pcv valve and the line going to it and the pcv grommet. and couple of other vacuum lines that looked crappy or cracked. Along with new spark plugs it has run great since, but it is possible that the pcv is gunked up if its original or one of the gaskets got pinched or a spark plug seal got ripped or is leaking. there is a lot of fiddly stuff up top there that may all be cracked and gummed up or brittle on a car with your mileage. Mine had right at 160k when I did mine as well. I had oil almost pouring out of the passenger side valve cover

 

 

The valve cover gasket replacement is not likely to be related to oil leaking into the combustion chambers. As jimbosr1 already mentioned, oil can leak through a bad oil seal from under the valve cover into the cylinder, but these sorts of leak will cause a steady oil burn, as opposed to what you described where the occurrences are intermittent. Spark plug gasket will cause oil to pool in the tube only. Unless the spark plug is loose, oil cannot enter the cylinder via this path.

A compression test can tell you if you have a leak in the cylinder. If a leak is confirmed, there can be 2 primary causes - leaky piston rings, or a leaky seal. Typically, you can pour a small amount of oil into the cylinder and repeat the compression test. If compression improves, then the problem is with the piston rings.

Another probable cause may be a defective PCV that is sticking intermittently and allows oil to vent into the intake air plenum causing the symptom you described.

 

The problem is most obvious after the car sits for a period of time, say overnight, and is then started. I keep thinking valve seals but I haven't been inside the heads of an automobile since the mid-1960's. I've made an appointment to have it looked at on 3/20/18 but as you can imagine it's a bit deflating to drive an attractive and well maintained Lexus that smokes. Thanks for all the input, will keep you informed - JL.

 

Just returned from dealership. Was told oil burning after valve cover gaskets were replaced was the result of "a valve needed tightening." However, paperwork said valve cover was loose and required tightening. I'm not sure what was done to my 2001 LS430 but it runs fine and doesn't burn any oil and it only took two hours. Thanks again for all of your input, it helped when speaking with service people at dealership.

 

Glad you got it fixed, but those two statements don't really make sense. Valve covers keep the oil inside the valley and off the outside of the engine. Valve cover gaskets are used in between the valve cover and the engine to help seal and keep oil where it's supposed to be. The valve is an internal part to the cylinder and can be found underneath the valve cover. To 'tighten' or adjust the valve they'd have to remove the valve cover completely, adjust the valve per spec and then put on new gaskets and re-install the valve cover.
How did the valve get 'unadjusted' in the first place?

This is like saying... my desktop computer wasn't working properly so they tightened up the cover and now it works fine. Really?
Not really sure what happened here.

 

Sounds like they found there screw up and fixed it then told you a song and dance story.Anyway you are good too go!

 

Those were my thoughts as well. I've changed valve cover gaskets and although it was many decades ago and automotive technology has changed significantly since then, I fail to see how tightening a valve cover resolved my oil burning problem. However, I was more concerned about a successful outcome than arguing the details of the repair and so far the LS is running well, although I really would like to know the specifics of the repair.