Wouldn't you be able to see down the plug hole to see if thier is a leak or some residue? Hopefully it is just a gasket. Did he have them painted/PC'd. Maybe just reused the old gaskets. Maybe they are just worn.

-'96 SE MTX 3L -'98 SVT 1,173 of 6,535 -'05 Mazda 6s, loaded, g/f's ride -Need a 96-00 manual on CD? PM or email me