Leakdown Test

1. Disassemble and clean valve tappet to remove all traces of engine oil.

NOTE: Do not mix parts from different valve tappets. Parts are select-fit and not interchangeable.

2. Place valve tappet in tester with plunger facing upward. Pour hydraulic tester fluid into cup to a level that will cover valve tappet. The fluid can be purchased from the tester's manufacturer. Using kerosene or any other fluid will not provide an accurate test.

NOTE: Valve tappets cannot be checked with engine oil in them. Use only testing fluid.

3. Place a 7.94 mm (0.31 2-inch) steel ball provided with tester in plunger cap.
4. Adjust length of ram so that pointer is 1.59 mm (0.062 inch) below starting mark when ram contracts tappet plunger to facilitate timing as pointer passes Start Timing mark.

Use center mark on pointer scale as Stop Timing point instead of original Stop Timing mark at top of scale.

5. Work valve tappet plunger up and down until valve tappet fills with fluid and all traces of air bubbles have disappeared.
6. Allow ram and weight to force valve tappet plunger downward. Measure exact time it takes for pointer to travel from Start Timing to Stop Timing marks of tester.
7. A satisfactory valve tappet must have a leakdown rate (time in seconds) within specified minimum and maximum limits.
8. If valve tappet is not within specification, replace it with a new valve tappet. Do not disassemble and clean new valve tappets before testing because oil contained in new valve tappets is test fluid.
9. Remove fluid from cup and bleed fluid from valve tappet by working plunger up and down. This step will aid in depressing valve tappet plungers when checking valve clearance.