90K
Expedition is used for emergent blood transport.
We are all volunteer and I am preparing to change the spark plugs.

Conflicting procedures on changing the spark plugs.

Expedition has brown boots over the spark plugs.
Does that mean we need not soak carbon solvent in the sparkplug wells to avoid breaking off the Motorcraft sparkplugs?

Surprisingly, Ford dealer service supervisor suggests Champion irridium spark plugs over Motorcraft spark plugs.

We cannot afford to break any spark plugs in the head. Must get the SUV back in service as soon as possible.

Your opinions and suggestions?

Thank you.