Testing Procedure
Tools Required
J 35667-A Cylinder
Leakdown Tester
With the use of air pressure, a leak test will aid in diagnosing cylinder
leakage. If necessary, the leak test may be used in conjunction with the engine
compression test, in order to help isolate the cause of leaking cylinders.
- Remove the negative battery cable. Refer to
Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing
any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to
the vehicle or its components.
.
- Remove the spark plug. Refer to Spark Plug in Engine Electrical.
- Install the J 35667-A
.
- Measure the cylinder on the compression stroke, with both valves
closed.
Important: It may be necessary to hold the crankshaft balancer bolt/screw, in order
to prevent piston movement.
- Apply air pressure, using the J 35667-A
. Refer to the manufacturers instructions.
- Repeat the leak test for each cylinder.
- Record the leakage readings for all of the cylinders.
Important:
• | Normal cylinder leakage is from 12 to 18 percent. |
• | Make a note of any cylinder with more leakage than the other cylinders. |
• | Any cylinder with 30 percent leakage or more is problematic. |
- Inspect the four primary areas, in order to properly diagnose a leaking
cylinder.
- If escaping air is heard from the intake system at the throttle
body, perform the following procedure:
• | Ensure that both valves are closed. |
- If escaping air can be heard from the exhaust system at the tailpipe,
perform the following procedure:
• | Ensure that bolt valves are closed. |
- If escaping air is heard from the crankcase system at the crankcase
(oil filler tube), perform the following procedure:
- If escaping air is causing bubbles in the cooling system radiator,
perform the following procedure:
- Install the J 35667-A
.
- Install the spark plug. Refer to Spark Plug in Engine Electrical.
- Install the negative battery cable.