I have a 2000 Civic CX, 125,000 mi and the plug wire on the #1 cyl. Frequently pops off. This happens as the engine approaches normal operating temp. If pushed back in place after engine reaches normal temp, it stays in place and runs fine until the next cold start. The occurrence is becoming more frequent which leads me to believe something is in the process of moving toward complete failure.

Plug is tight. Wires are new. I can't figure out how pressure is getting outside of the engine. Any suggestions?

Ensure the spring connector fits properly over the top electrode. It needs to be squarely centered.

Checked the connector yesterday and it is good. Centered well and not out of round. The grommet on the end of the plug wire is snug in the tube. No oil in the tube but the grommet smells like oil and has a sooty type of residue on it. Other grommets are clean and smell like a rubber grommet smells. Wire popped of again this morning. I read on another forum about an o-ring on or near the bottom of the tube. (nothing like that on my old Chevy 350) I am not familiar with this set up but could that be the problem?

This is a strange occurrence. I can't really imagine a normal explanation for it, unless those are aftermarket wires that really don't fit properly. That would be my guess. What brand are they?

Old wires are supermax 7mm, highest quality sold at the local oreillys. Replaced those with OEM. The grommets on the old wires are larger than the OEM and are snug in the tubes to the point that they make a small "pop" coming out of the tube. Should have noticed that putting them on. The OEM grommets have millimeter or two clearance. My bet is that this will solve the problem of the wire popping off since the pressure can pass. Honda tech says the plug tube seal in the valve cover may be the source of the pressure. Thoughts?

He has a good point about the seals. I used to replace them on my old Toyota. Valves had to be adjusted yearly, so he cover had to come off.

I would think there should be a sign of a small leak. Put some baby powder around and on the end seal and look for anomalies.

Meanwhile, get a tywrap and use it to fasten the boot.

If it is the end caps there should be a small amount of oil consumption.

It can also be a pressure-temperature issue.

OEM wires seem to have solved the symptom. No problem today. The next few days will tell. I will keep an eye on it and see if I can figure it out. Good news is the parts are cheap. Seals and valve cover gasket . $22 plus tax and an hour or two... I am a slow mechanic. Anything special on the installation of the seals?

As I said, sprinkle some baby or talcum powder on the seals and look for signs of oil.

I don't know how Honda did it, but Toyota put two step collars on the valve cover. Remove the two nuts and the collars and then slide the cam cover to break the seal.

The Cam cover gasket was like an O ring with an O ring groove, etc. Traditioal gaskets and just plain goop have been used on other manufacturers.

When I replaced the cam cover plugs I just out a film of oil on them. Same for the O ring.

With Foreign cars. My experience has ben the OEM parts are better than the aftermarket. Just the opposite for domestic cars.

Coat the spark plug seals with engine oil, where they contact the spark plug tubes. Tighten valve cover bolts 7 lb.-ft.

Many thanks to you both. Will let you know the final outcome but it may be a couple weeks

Great. Here are some tips to keep your Civic going a long time:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563.html#post219991