1. Gather the necessary tools. You will need:
* A set of feeler gauges
* A 10mm wrench
* A screwdriver
* A rag
2. Prepare the truck.
* Disconnect the battery to prevent accidental starting.
* Allow the engine to cool down completely.
3. Locate the valve covers. There are two valve covers, one on each side of the engine.
4. Remove the valve covers. Use the 10mm wrench to loosen the bolts holding the valve covers in place. Remove the bolts and then carefully lift the valve covers off of the engine.
5. Inspect the tappets. The tappets are located between the camshaft and the valves. They are small, cylindrical pieces of metal. Check for any signs of wear or damage.
6. Adjust the tappets. If any of the tappets are not within specification, you will need to adjust them. To do this, use a feeler gauge to measure the gap between the tappet and the valve. If you find any tappets that are too tight or too loose, loosen the locknut and use the screwdriver to turn the adjusting screw until you have adjusted the gap to within specification.
Make sure the locknut is tightened securely before proceeding.
7. Replace the valve covers and reconnect the battery. Once the tappets have been adjusted, you can replace the valve covers and reconnect the battery.
