Disclosure / Liability Issue: One or more spark plugs were discovered to be seized or extremely difficult to turn on your vehicle’s engine. Any further attempt to remove them may result in thread damage requiring additional repairs. Before proceeding with customer authorization our repair facility requires that you understand the risks involved with the repair process and are willing to accept those risks.
In the course of performing an engine tune up involving the removal of the engine’s spark plugs we are starting to see more engine cylinder heads that have seized spark plugs. While may vehicle manufactures have designated that their engine designs do not need to have the spark plugs changed until 100,000 miles or more. What we are seeing in the service bay is that steel threaded spark plugs are not made to last for extended periods in a hostile environment with aluminum designed engine cylinder heads. Basically steel and aluminum do not co-exist well for extended periods. In extreme cases corrosion sets in and the result is the spark plug threads become seized into place. While removal is possible with a lot of special extraction techniques some cases may result in cylinder head thread damage. While this is rare we have the capability to repair the damaged threads with the installation of a spark plug insert. In the event this occurs we have been successful in installing an aftermarket plug thread insert into the engine cylinder head with the engine still installed into the vehicle. The procedure involves the installation of a heli-coil device. Specialized tooling is required to make the necessary repairs. Please be advised that additional labor may be required depending upon cylinder location. There is no warranty expressed or implied on thread insert repairs.
Advisory: In extreme cases the possibility exists that cylinder head removal may be required to properly complete the necessary repairs if the initial repair attempt in installing a cylinder head thread insert is unsuccessful. Every effort is made to minimize the possibility of this occurring. Appropriate charges will apply to perform the necessary corrections. Be advised that once this process starts there is no way to return the engine to its original condition if additional repairs are required.
The Repair Process for The Installation of a Thread Insert: identified damaged spark plug threads after removal of seized spark plug, machined hole with cylinder head still on engine to accept replacement insert, installed replacement steel insert which is significantly stronger than the aluminum cylinder head, installed new spark plug, ignition coil and any removed components to gain access. Cleared computer memory and verified normal operation.