How to Torque a Head
- 1). Check a maintenance manual to find the amount of torque the manufacturer recommends on these particular heads. Check to also see if they are called torque-to-yield bolts. Some engines use these bolts, and they can only be torqued once. They need to be replaced if removed.
- 2). Place some anti-seize compound on the threads of all the bolts. If you're working on a V-8 engine, add some RTV to the short bolts that go in the lower part of the head by the exhaust ports, and put it at the top of the threads and a quarter way up the shank. The reason for doing this is the fact that they are more susceptible to leaking antifreeze--the RTV fills up any spaces to help prevent leaks.
- 3). Install the bolts and tighten them loosely (with no torque) with the ½-inch socket and ratchet.
- 4). Set the torque wrench to 30 foot-pounds of torque. Begin to torque the head starting on the center bolt. Torque the remaining bolts from the center outward using an "X" pattern. Go from the center bolt to the closest upper right and then the lower left, then the lower right and upper left and so on, working outward. When finished, set the torque wrench to 60 foot-pounds of torque and repeat the process.
- 5). Set the torque wrench to the final torque suggested for the vehicle after the bolts have been torqued. If they are standard bolts, once the final torque is applied, it is finished. If they are torque-to-yield bolts, it will say torque the bolts to, for example, 90 foot-pounds, and then an additional 90 degrees. For these bolts, torque down the bolts to the final number, then put the torque wrench handle at the 3 o'clock position and turn it clockwise to the 6 o'clock position to finish.
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