Last weekend I changed the spark plugs on my brother's 04 Tiburon V6,
as it was approaching 60K miles. Besides the usual complaints of what
a PITA the job is, I ran into a couple of problems.

1. When removing the front 3 plugs, #1 came out easily as expected,
but #2 & #3 didn't want to budge. With the help of an impact wrench,
gently applied, both came out without incident. The #1 was only slightly
worn with a 1.15mm gap, the #3 plug had a 1.2mm gap, but the #2 plug
was severely worn with a 1.8mm gap, but no fouling, discoloration or
damage.

The 3 rear plugs came out easily, and the gaps were uniformly 1.05mm.

The radiator overflow was nearly empty and the coolant in the radiator was
down about a 1/2". I needed a few ounces to top it off, and about a pint
to fill the overflow bottle to where it should be. The engine has never
overheated or even gone above the normal temp, and the coolant level
hasn't been checked in over a year.

Could this engine have a small head gasket leak near the #2 plug? Would
a coolant pressure test (when cold?) detect a really small leak like this?

2. When reattaching the throttle body to the intake with a torque wrench
set to 13 lb/ft, the two bolts tightened down as expected, as did one of
the nuts on the the remaining studs. But the other nut didn't seem to
tighten
up, and I stopped at a point fearing I was somehow stripping out the stud
from the manifold, and I wasn't about to take the whole thing apart to find
out. There aren't any leaks and the engine performs well.

The engine has never had a need to be worked on since the car was
bought new. Could this be considered a factory defect, and would it
be covered under warranty? If I brought it to the attention of the dealer
service dept, would they replace the upper manifold or just try to
stabilize the stud with some Locktite? Or would they just blame the
owner for daring to change his own plugs?

Bob