1997 2.2L with 140k miles. Replaced spark plugs and notice 3 of the 4 spark plug boots were oily. Two of them had oil pooled up in bottom of spark plug tube. This is my first 2.2L engine. After this post, I will try to find an exploded view of the valve cover and hopefully an explanation of how the spark plug tubes are affixed. Spark plug threads were dry and engine exhibits minimal oil consumption. How is this oil migrating into the tubes? Are there gaskets, seals or o-rings that seal the tubes. Will the solution include a complete valve cover gasket replacement? Thanks for any help.

 

The issue is not uncommon. YouTube has lots of videos on this to review.

The spark plug tube extends from the large nut on the outside of the valve cover to the cylinder head. Depending on the year of engine this tube is either held into the head by press fit or threaded into the head. When first installed into the head Toyota used sealant as an extra precaution against leaking.

There is a large rubber gasket at the top of EACH tube on the valve cover end to keep oil out the tube at this end.

If your thinking about removing a tube for reseal read up first on methods and tools as one can easily damage the tube removing it.

See private message.