I’ve got a 1997 ES300 and I noticed something odd about it’s oil burning. A couple months ago it was burning about a quart of oil every thousand miles. One day, one of the spark plugs decided that it didn’t want to play anymore and went bad. All I did to fix it was change just that spark plug. A week or so after that I changed the oil. It’s been a little over 2,000 miles since that oil change and its only burned about half a quart. Don’t get me wrong, I’m not complaining about it going from burning a quart every thousand to half a quart every two thousand, but I’m just confused. All I did was change out a single bad spark plug. The plug wasn’t covered in oil and there wasn’t any oil in the spark plug hole. Any explanation for this? I used the same oil and filter as I always do.

 

Hello,

What do you mean by "failed" plug?
Are you sure the oil is being burned instead of leaking?

Spark plugs usually don't fail one-by-one, you either have a bad set, or the other plugs will be soon to follow. It is always a good practice to replace all the plugs should one fail, especially if by "fail" you mean an electrode falling off or ceramic casing crack.

As for the oil, my only guess would be that the Piston Rings may have gotten seized, causing engine to eat oil. The proper way to solve it would be to take the engine apart and replace them, but in your case, I heard people have some success unseizing the rings by removing the plugs and pouring some Seafoam or other leaner in each cylinder, letting it sit for a few days, below is the video I found about it.


Hope this helps and best of luck!

 

It was a single plug that failed and caused a misfire on one cylinder. The car doesn’t leak a drop of oil. I was in the middle of a road trip and just changed the one that was bad. I’m not concerned about the oil burning, I can live with it burning a quart every 4,000 miles, I just don’t know why changing that single plug was cause such a drastic decrease in oil burning. Also, the oil burning is mainly from the valve seals in my car’s case. If the car sits overnight, it’ll sometimes greet me with a cloud of blue smoke when I start it up the next day.

 

No combustion on a cylinder causing oil to put pushed into said cylinder due to lack of pressure?