Ford 2007 Town Car Owner's Manual page 309

Maintenance and Specifications
equivalent replacement part. The customer warranty may be void
for any damage to the emissions system if such a PCV valve is not
used.
3
For spark plug replacement, see your authorized dealer. Refer to
scheduled maintenance information for the appropriate intervals for
changing the spark plugs.
Replace the spark plugs with ones that meet Ford material and
design specifications for your vehicle, such as Motorcraft or
equivalent replacement parts. The customer warranty may be
void for any damage to the engine if such spark plugs are not
used.
308
2007 Town Car (tow)
Owners Guide (post-2002-fmt)
USA (fus)