#4 spark plug on my '05 Odyssey EX appears to have corroded so badly that the spark plug socket won't fit it. It felt like it was unscrewing, but then wouldn't come out. I later tried to hammer the socket onto it (not too hard), but it wouldn't go, which is weird, since you'd think the socket would fit over a corroded plug MORE easily. Ever seen this before? And more to the point, how might I go about removing it? I'm thinking the valve cover will have to be removed. I'll try to take a closer look at it tomorrow: will update with any new info. Thanks. Dave

 

The plugs are porcelain. Do not hammer them! If you brake a plug you will only get more problems.

Try to get a mirror and look into the spark plug well to see what is going on.

Change socket to a smaller size.

Good luck,
Sam

 

Thank you, Sam. I had a mirror and a flashlight, and all I could tell was that the outline of the plug was uneven. At first, the plug seemed to unthread disturbingly easily: I thought "Holy crap: that plug was loose!", and because the extension appeared to be moving out of the spark plug well as I (thought I) was turning it, I thought it was, indeed, unthreading. Assuming it was loose, I spent half an hour trying to extract it from the spark plug well, before I realized it was still in there tight. Any thoughts on what might have caused the plug to corrode (if that's what it actually is)? I'll try to find time to take another look tomorrow.

 

Sounds like it was possibly mis-threaded the last time it was installed, if it is not sitting in there evenly. Getting the socket to grab might require a good amount of force, if it will at all.

Good luck

 

Try to tighten/untighten it few times.

Get a longer tube and spay some penetrating oil to the plug's contact surface.

Good luck,
Sam