Full Gasket Set Head Bolts Fit 96-00 Toyota Tacoma 4Runner T100 2.7L 3RZFE. The head gasket is the key component of the engine. It is compressed between the engine block and the cylinder head. The head gasket seals in the internal combustion process to make sure maximum compression is achieved and also keeps coolant and oil from mixing together as the two fluids travel from the engine block to the cylinder headr. Head gasket set is combined with a conversion gasket set / lower gasket set to form a full gasket set for the entire engine.. Time will come that your head gasket will leak or blow. The cylinder head bolts hold the cylinder head and cylinder head gasket in place and ensure that the cylinder head will continue to hold up despite the tremendous amounts of pressure in the combustion chamber. Therefore the cylinder head bolts, and cylinder head gasket are an important part of your engine. They should always be in perfect condition and should be maintained properly. So, if you notice that this part is showing signs of excessive wear, have them replaced immediately. Be sure to have your engine gaskets, and head bolts replace with aftermarket replacement head gasket bolts set as soon as it starts to give you trouble.