Stop in for a cup of coffee

Yup. Helicoil kit. Think i pay $7.00 for each sleeve. Worst ones are back 4.
Junk. I did plugs on a truck, think torque was 30 ft-lbs and about 2 years later the plugs started blowing out. Wrecks coil almost every time.
I sold a steel insert set. It came with a reamer and a tap. The steel inserts were a solid fix.