Do not repair spark plug port threads in aluminum cylinder heads-
Unapproved usage of helicoil for serice
Some engines equipped with aluminum cylinder heads may exhibit spark plug port(s) with stripped or missing threads, "Do not" service stripped or missing spark plug port threads by using "helicoil" or "tapersert" repair kits. It is likely that additonal engine damage or engine failure will occur after an unsuccesful atttempt to service the cylinder head spark plug reports with "helicoil" or taperset. The only authorized service procedure is to replace the cylinder the cylinder head assembly when spark plug port threads are damaged is to replace the cylinder head assembly when spark plug port threads are damaged and in need of service, refer, to the pertinent workshop manual (section 303-1) for cylinder head removal and installation procedures. Note: When servicing spark plugs for any reason , do not use air or powertools and take care to ensure that spark plyugs to not crossthread.