We receive many questions regarding insert failure, many of which
we find are the helicoil or Save-A-Thread spark plug style. The Helicoil
spark plug insert is black in color and has a knurl at the top to keep it
in place by hitting the top of the insert with a mandrel and a hammer.
Insert O.D is .660 inches.

On Ford vehicles spark plug repairs use
6605553. Import vehicles
we offer the
p/n 660
5141E or 6605141S kit.

Special note: If repairing a Ford with p/n 6605553 kit (Check casting number
to see if you will use the counterbore
p/n 66255518 or not use the counterbore)

The 66255518 counterbore stops on the original taper seat built into the head.
This original taper seat would not exist because it was removed due to the
first failed repair with the helicoil / save-A-thread style inserts.  We need to
check the casting number on heads 2001 and up for the RF-1L2E number.
If the number exists on the previously repaired head you must use the
counterbore tool "Manually" to remove a step found in the head.

Click here: for more information on counterbore for FORD 2001 and up 1L2E


Helicoil spark plug kit failure
Helicoil insert failure


The Very Best in Ford spark plug thread repair!
P/N 6605553