Some of these engine are known to have a problem with breaking spark plug off below the threads. This
would make it impossible to remove them without removing the heads if it wasn't for the special tools they
make for just this reason.
https://www.amazon.com/dp/B00267PZU...olid=2YFIUJ8JWFA6F&psc=1&ref_=lv_ov_lig_dp_it
As I said above, some of these engines have this problem. You can tell what you have by a couple of
different methods. The engine date code on the cam cover (valve cover) on the driver side. The engines
with a code before 10/09/07 used the problem plug above, dates after that use a newer design below.
I used the Champion 9406 which is the later design in my 2008 Lincoln Navigator. The old design are
very expensive, they cost $20 each at Advance Auto.
Second method is looking at the boot color, BLACK is before and BROWN is after.
Later Better Design
Problem Design
Before removing the coils, be sure to blow out the recess with compressed air. Do the same again after
you remove the coils. Notice is the pic below, the spark plug is entirely surrounded by the recess in the
head. Don't want any rocks or debris falling into the cylinder. A magnet is helpful to get the spark plug
out.
Plugs 2,7 and 8 had noticeably larger gaps than the others. The gaps were .050", .050" and .054". The
factory gap setting is .040". These plugs have 95,500 miles.
The new plugs are gaped at 0.044" .
.
would make it impossible to remove them without removing the heads if it wasn't for the special tools they
make for just this reason.
https://www.amazon.com/dp/B00267PZU...olid=2YFIUJ8JWFA6F&psc=1&ref_=lv_ov_lig_dp_it
As I said above, some of these engines have this problem. You can tell what you have by a couple of
different methods. The engine date code on the cam cover (valve cover) on the driver side. The engines
with a code before 10/09/07 used the problem plug above, dates after that use a newer design below.
I used the Champion 9406 which is the later design in my 2008 Lincoln Navigator. The old design are
very expensive, they cost $20 each at Advance Auto.
Second method is looking at the boot color, BLACK is before and BROWN is after.
Later Better Design
Problem Design
Before removing the coils, be sure to blow out the recess with compressed air. Do the same again after
you remove the coils. Notice is the pic below, the spark plug is entirely surrounded by the recess in the
head. Don't want any rocks or debris falling into the cylinder. A magnet is helpful to get the spark plug
out.
Plugs 2,7 and 8 had noticeably larger gaps than the others. The gaps were .050", .050" and .054". The
factory gap setting is .040". These plugs have 95,500 miles.
The new plugs are gaped at 0.044" .
.
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