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Oil on spark plug

car was running sluggish with a skip . i took out the plugs and one had oil on it. put in 4 new plugs and car ran good again. but one plug has oil back on it. remedy anyone???

Carmodey, What Is The Model-Year Of This Corolla And About How Many Miles Are On It ?

CSA

the mileage is 145,000 and is a 1999

Do you burn any noticable amount of oil or have blue smoke in the morning?

Mr Obvious, Here. Where Is The Oil ? On The Plug’s Electrode(s) Or On The Outside Part Of The Plug’s Metal / Threads, Porcelain ? Is The Oil Wet Or Just Black Soot ?

CSA

Also, was the oil on the back end of the plug that sticks out above the head or the “business end”? Many of these engines use plugs sunken into “spark plug tubes” to get below the overhead valvetrains and if the tube seals leak oil can get on the plugs.

By the way, how old were the old plugs and what did they look like? Can you compare them to the chart linked below?

oil is on the threads and oil is wet

A Little Oil On The Outside Of The Threads Isn’t A Big Deal.

There are tubes like TSM talks about that contain the sparkplugs and allow them to screw into the cylinder head without sitting right in the oil that’s splashing around under the valve cover.

An o-ring seal at the top of the tube that has the wet plug has started to leak a little and drip into the bottom of that tube. As long as your spark plug wrench wasn’t dripping with oil then it shouldn’t be an emergency.

It doesn’t look that difficult to replace the valve cover gasket and spark plug tube o-rings on that Toyota.

I doubt that problem was causing the poor running of the engine.

How long and how many miles were on those plugs you took out ? Any idea ? It just might have been over due for new plugs or you’ve got old plug wires, etcetera.

How’d the electrodes look on the tips old plugs that were inside the engine ? Were they all a beige color ? Were they all pretty much the same color ?

Take a look at the chart TSM links you to, below.

CSA