So is there a place to get the right socket for them? I got one from Auto zone & one from Amazon. They are only like a mm larger than the round base under the hex nut. Is there a thinner socket available somewhere?
These may need to use the "socket" part of the spark plug socket to help with reach.
Meaning that the plug may be too long for the socket to fully reach the nut on the shell of the plug - because the socket may be a spark plug type, but if the terminal is interfereing with the "square" of the 3/8's socket
The problem may not be with the width, more the depth - meaning that when you use a 3/8 - ratchet, the "3/8" used to hold the socket is the problem - the clearance of the terminal - because of the length (Height) of the plug is a potential problem.
The grommet used to hold the plug in the socket, can also add a fitting problem - the grommet can't fit the insulator - the hole for it may be too small for the insulator so it's too tight to fit. So, you can't seem to push into the hole to hold the insulator, so it doesn't break and let the tool seat the socket onto the nut of the shell.
There's some grey area of conditions of you can encounter with plugs and issues around both the boot, the "coil on the plug" and these in seat types of designs - where dirt, debris and age can erode the boot to make it difficult to remove the plug because there is so much dirt and debris in the hole to keep the socket lifted away from the shell so it can't even reach the nut let alone fit the hole.
From a Ford Focus...
So, if you get the whole boot out, what is still in the hole - is there dirt or debris?
So, we need to know what kind of conditions or what you're experiencing?
My car is only 4 years old and clean. No debris in there. The socket with the rachet extension fit right down on the new not installed plug so the depth of the plug into the socket is no issue. I even tried with extension only half way in. The issue seems to be the clearance of the block bore size around the old plugs hex nut. The socket is like 1/16 than the new plugs round base just under the hex nut. I think the bore is only as big as the plug I’m considering grinding down my socket wall a bit. It seems they’d sell a special socket for this job. Thanks engineers- grrr. I appreciate your explanation and I’ll try again.
I've used my own purchased decades ago - so I'm surprised to know this...er, socket - size problem.
Remember too, the tool fits the current NEW plug, I've owned vehicles that have had plugs from their OEM versus say a different brand like - Champion - have a different "hex" nut size - so one you (finally) get the old plugs out - you can switch to the new and if they are working for the correct heat range and gap size with the performance you'd expect - that's pretty much what you stick to.
It's also one of those "games" makers play to keep you from going overboard and using wrong plug types. Toyota and Suzuki were notorious for this... (still are in one fashion or another)
Just wondering - are you keeping the same plug or using something different to upgrade it?