i was changing the spark plugs, and noticed that there was a hint of oil on one of the ignition coil on the back middle cylinder. But on the back right cylinder the ignition coil had a lot of oil, even on little bit on the spark plug.
i suspect that the seal is leaking.
actually recently changed those, but may be not set properly. is there a correct procedure to set those seals?
what happens if the seals are not replaced?
does that oil harm anything?

 

The oil cools the coil internally, excess heat = death to coil
You replaced which seals? and now they leak,,,,maybe a new part is in order

 

i replaced the GASKET SET, HEAD COVER, which included the SEAL,SPARK PLUG.
is there a special way to insert it. i did it the best way could. any tips?
i never paid too much attention there.

 

I did a little looking into that a while ago, my valve covers need to have their gaskets replaced too. The seals around the coil tubes have to be set properly and I've heard people say they are temperamental.

 

i did not read anywhere people say anything specific about these seals, and if something can go wrong. so i just installed it the best i could and did not bother. until i opened the coils to replace the spark plugs.

 

You can install the plug well seals backwards, and you can tear them as well. Did you look in the plug well when you did the gaskets? The oil could have been there before. Clean it out with brake cleaner and compressed air, or a rag soaked with brake cleaner twisted around a screwdriver. Check it again in a few days, if no leak, check it again in a month or so.

 

i installed the seal the same direction i removed the old ones. How can i say which way is the correct side. looking at the drawing i think i installed it the right way.
the oil was not there before, as the first time when i removed the coils, there was no oil on either of the coils. but this time there was.

 

Especially since the oil wasn't there before, you should pull the valve cover and really inspect that seal.

 

could seafoam have caused this?
After installing the new gaskets, i did a seafoam. 10oz TB, 10oz gas tank, 10oz engine oil.?

 

seafoam does not cause leaks, its basically 3 types of oils that clean and lubricate

Please everyone follow the ratios as I have given many times- came direct from Seafoam head tech guy:
Gas tank 2 oz per gal of fuel, use 1 can to just under half tank 2 times (no need for vac method then, but still need to clean TB air plate)

Oil 1.5 oz per QT of oil and 15 minutes to 100 miles drive before change with fluid warm

Mater Vac port/TB inlet 1/2 can, Deep Creep- seafoam aerosol recommended over liquid.
Can be tricky to do right thru vac port= fuel tank gives a much more effective treatment for your dollars!

 

In order for you to have oil on the coils you'd either have to have

1) A leaky coil tube grommet
2) A cracked coil tube
3) Leaking piston rings and a broken/loose spark plug

I think #1 is a lot more likely

 

the gas tank was less than a quarter tank, so i used 10oz
the oil is around 5 qt, and i used 10oz. changed oil after 30miles.
10 oz for the vac port/TB (when you say aerosol you mean the seafoam spray)

 

1. What is the coil tube grommet? part number? photo? drawing?
2. need to inspect that
3. new spark plugs.

 

we use 1/2 tank gas to full can of seafoam in order for it to have time and heat to clean the system
Seafoam friends, time and heat

 

I suspect he's using a different term for the same part you just installed. ie, plug well seal = plug tube seal = coil tube seal = coil tube grommet. Typically, in this instance, the rubber seals under the valve cover bolts are called grommets.

 

There is a video out there how to unscrew the tubes and do it properly. cant find it right now. its by EricTheCarGuy