3sfe spark plug tube oil leaks

[chubcobear]

After reading several posts on this forum, it appears that 1990 (1987-1991) 3SFE engine spark plug tubes are pressed into the cylinder head. therefore, it makes sense that when there is a small amount of oil in the bottom of the spark plug tube, it is because some person has tightened the 30mm nut on the cam cover too much. Is the pressed joint in the head leaking oil into the plug cavity? Can this minor amount of oil cause a plug to short out? It would not appear to be so, but perhaps I am wrong?
I am finding a small amount of oil in the bottom of cylinder two spark plug tube when I change plugs. I am wondering if that causes the minor engine stumble (miss) I have at idle? Could the plug be shorting out? Any ideas? Thanks.
Tom Bear

[GregElliott]

I have the same problem.. my spark plugs #3 & #4 had oil on them when I checked them... so I'd like to know where it's coming from... hopefully just from leaky tube seals.

[chubcobear]

Greg,
I'm thinking that over-tightening (or old age vibration) loosens the spark plug tube base (which is pressed into the head) and allows small amounts of oil to leak by into the spark plug well in the head.
A mechanic friend of mine just told me that the small amount of oil in the spark plug tube will not short out the spark plug, so we have to look for another reason for low idle stumble (missing), perhaps a vacuum leak, et.al.
There is also a tool for removing and inserting spark plug tubes into the head, however I don't know what it is.
In my Camry, I can see that the cam cover tube nut on #2 was tightened too much (perhaps to try to stop a cam cover gasket leak) and probably caused the tube base to leak a little.

[fredk]

you cant get those tubes out of the head with a 5 ton truck pulling on them, now if you got the motor hot enough and the head grew and turned the tubes loose you might get a little lift from the valve cover pulling upwards but you would have to tighten the nuts down enough to deform the valve cover, the tube seals are leaking a little

[chubcobear]

Fred,
What and where are tube seals?

[atobe]

the tube seals are right under those 30mm nuts that's covered by the spark plug wires. it's torque spec is quite low.. i think 20ft/lbs.. i once had sparkplug #1 swimming in oil i replaced valve cover gasket + spark plug tube seal = no more oil on spark plug

[new echo owner]

The spark plug tubes are screwed into the head according to the FSM.

N.E.O.

[chubcobear]

Thanks N.E.O.,
If the spark plug tubes are threaded at both ends, not pressed, then it follows that I can remove the cam cover, thread two tube nuts against each other onto the tube to make a bolt head and then back out the tube that is leaking. Clean the threads, use a good heat resistant sealant for the threads, and re-install the leaking tube nice and tight. That should stop the oil leak. I'll let you know how it goes. T. C. Bear

[new echo owner]

Roger that! Keep us posted!

N.E.O.

[GregElliott]

here's a good question... if I only have 2 plugs showing oil... could I get by with replacing just those tube seals or should I go ahead and replace all 4?

[new echo owner]

You can, but the question I would ask is why? It doesn't take much more work to do all, and you won't need to worry about it anymore.

N.E.O.

[Mike Gerber]

"it's torque spec is quite low.. i think 20ft/lbs"

The correct torque is 17 ft/lbs.

Before doing anything else I suggest you remove the oily spark plug and clean the oil out of the well. Then reinset the plug and torque all cam cover 4 nuts down in 3 even passes (6 ft/lbs, 12 ft/lbs and then 17 ft/lbs) going from plug 2, to plug 4, to plug 1 and finally to plug 3. This recompresses the oil seals under the nuts evenly and usually stops the leak. You can easily check for leaking oil later using a white wire tie as a dipstick. If you find that you are already over these torque values or if you oil leak continues, then you can get new top tube seals and install them and torque to spec.

Mike

[GregElliott]

Originally Posted by new echo owner

You can, but the question I would ask is why? It doesn't take much more work to do all, and you won't need to worry about it anymore.

N.E.O.

sorry, I got confused and was thinking about replacing the whole tube.

[new echo owner]

Originally Posted by GregElliott

sorry, I got confused and was thinking about replacing the whole tube.

Not a problem!

N.E.O.

[nogard]

If I miss anything please fill in the blanks and if someone feels like moving this or sticky it go ahead if you think it is worth it. I hope this helps. I would say this is a very simple job a newbie could do with simple tools and common sense. This was all done on a 1999 camry 5S-FE auto. I always thought the 3S-FE also had threads on both end of the tubes. I didn't think they were pressed it.

I would go to the dealer and get all the parts that is what I did. It didn't cost that much. The dealer here offers 10 percent off if you have over 100,000 on the car. I got new plugs, wires, tube seals, and thread sealant. I can't remember but I think I reused the valve cover seal.

1. Disconnect the battery, it is for your safety, remove the negitive. I highly recommend taking the hood off, It sounds like a pain but it is very easy and I do for most of the more involved work. And the way this engine lays back. If you don't you will have a sore back leaning under the hood, but to each there own.

2. Take the spark plug boots off. I left the spark plugs in the whole time to keep anything from falling into the cylinder and threads.



3. Loosen the spark plug tube nuts. These are the large nut under to spark plug boot. And take the tube seal off, it is under the nut.



4. Carefully take the valve cover off. A rubber mallet might help, hit the side of the valve cover to knock it free. I've learned in the past that the design of the rubber valve cover gasket is superior and usually will not leak if reused. But do as you see fit.





5. I did this a while ago, but I think I just used a channel lock or pipe wrench to remove the tube. Just grab it on the middle outer section and turn it out. It might be a good idea to sharpie the number on the side to put them back in the some cylinder.

6. Clean the old sealant off the tubes. I used a wire wheel on a bench grinder to clean out the threads.



7. Put new sealant on, follow directions on tube. Thread into head.



8. I put a nut on the tube. I held the tube with a pipe wrench and tightened the nut about 5-8 foot pounds more than the final tube nut torque when every thing is done. Then I used a large socket on a torque wrench to tighten the tubes in a few foot pounds more than the final torque on the tube nuts. Remember this is a steel tube going into an aluminum head. The sealant should do most of the sealing, not the tightness of the tube. It just needs to be tighter than the nut will be so it will never want to spin when you install and remove the nuts when the valve cover is on. Once the tube was in place, I put the pipe wrench on the tube and took the nut off. Once all four are done then put the valve cover on.



9. Clean off the valve cover seal if reusing, and clean off the matting surface of the head. You might want to put a small drop of oil and the four corners where the flat part of the head goes to the half round where the cam sticks through. Then put a little black RTV sealant at each of these points. Then put the valve cover on. The oil will keep the RTV from fully sticking to the head the next time the valve cover is removed. Also if the valve cover seal is going to leak it would be at this point. I had a new one leak on a tercel and I had to do this trick.

10. Put the new tube seal over the tubes.

11. Put the tube nuts on and torque to the listed spec. in manual.

12. Put new spark plugs in if you choose, and new wires on.

13. Reinstall hood.

Now that wasn't so hard! Just a little time consuming