Catalog each part as it is removed. Either take pictures or write down each part to help you remember where everything goes once you’re done. The cylinder head is held on by several bolts and some engines have a sequence for the bolts’ removal. Some head bolts cannot be reused and must be replaced. Follow the manual and manufacture requirements. Once all head bolts are out then lift the cylinder head off of the engine block. Look at the head surface and the block along with the gasket for the failure areas. The gasket will be a thin piece of sealing material that can be seen once you remove the head. The gasket can be made out of metal, deformable material, or a combination of both. The failure can be a break in the gasket.
Check the service manual for the head bolt specifications to see if the bolts need to be replaced whenever the head gasket is replaced. Some bolts are what is called torque to yield type and would need to be replaced The cams on overhead cam motors will need the cams removed to service the cylinder heads. Talk to the machine shop that is working on your heads about what needs to be removed before having them work on them.
Overhead cam heads may need the cams to be in a set position before the head is installed, or installed after the head is installed to keep the valves from contacting the pistons and bending them.
Make sure the engine does not overheat during the purging process, or head gasket or head damage could occur again. Once all air is out of the cooling system and engine temperature is stable and in the normal range, check for any leaking oil or coolant.
