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. see below pictures. The Helicoil insert O.D measures .660 inches.

On Ford vehicles spark plug repairs use p/n 5553. Import vehicles we offer the p/n 5141E or 5141S kit.

Special note: If repairing a Ford with p/n 5553 kit (Check casting number to see if you will use the counterbore p/n 55518 or not use the counterbore)
The 55518 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 heads.