The 1999 Ford F150 was equipped with a 2.4-liter, 6-cylinder engine as standard equipment and made available with the 4.6-liter and the 5.4-liter, 8-cylinder engines as optional equipment. The 6- and 8-cylinder engines have different fastener tightening specifications, which ensure that the component's gasket seats properly and that the component does not warp or crack upon installation.
Tighten the 4.2 liter's intake manifold fasteners to 8 pound-feet of torque. Note that the 4.6- and 5.4-liter engines each have an upper and a lower intake manifold. The tightening specifications are the same for both engines. Tighten the lower intake manifold fasteners to an initial setting of 18 pound-inch of torque. Then tighten the fasteners to 5 pound-feet of torque. Tighten the lower manifold's fasteners again to 9 pound-feet of torque. Tighten the upper intake manifold's fasteners to an initial setting of 11 pound-feet of torque. Then tighten the fasteners to 22 pound-feet of torque.
Tighten the exhaust manifold fasteners on the 4.2-liter engine to 22 pound-feet of torque. Tighten the fasteners on the 4.6- and 5.4-liter engines to 20 pound-feet of torque.
Tighten the 4.2-liter's cylinder head fasteners to 14 pound-feet of torque. Then tighten them to 29 pound-feet of torque. Tighten the fasteners again to 36 pound-feet of torque. Then loosen all head fasteners three revolutions. Tighten the shorter fasteners to between 15 and 32 pound-feet of torque. Tighten the longer fasteners to between 30 and 36 pound-feet of torque. Finally, tighten all of the 4.2-liter's fasteners an additional 180 degrees. Tighten the 4.6- and 5.4-liter's head fasteners to between 28 and 31 pound-feet of torque. Tighten all fasteners an additional 90 degrees. Finally, tighten the fasteners 90 degrees again.
Tighten all but the 4.2 liter's rear cap to 91 pound-feet of torque. Then tighten the rear cap to 88 pound-feet of torque. Tighten the 4.6- and 5.4-liter's vertical cap fasteners to 32 pound-feet of torque. Then tighten each vertical cap fastener an additional 95 degrees. Torque the horizontal fasteners to 24 pound-feet of torque. Then tighten all horizontal fasteners an additional 90 degrees.
Tighten the 4.2-liter engine's connecting rod caps to 29 pound-feet of torque. Then tighten the cap fasteners again by 90 degrees. Tighten the 4.6- and 5.4-liter's rod caps to between 29 and 34 pound-feet of torque. Then tighten the cap's fasteners an additional 90 to 120 degrees.
