14. Crankcase Pressure Test

14. Crankcase Pressure Test

Note: Verify the engine oil level and quality. Refer to Check Engine Oil Level in this section.

Purpose:

The purpose of this test is to measure the crankcase pressure. Crankcase pressure is a measure of how well the cylinders are sealing.

With the engine at 80°C (176 °F) minimum measure the pressure at the oil fill tube with the 6.OL Crankcase Pressure Tester 303-758 or equivalent. Block the breather tube on the lefi valve cover and measure with no load at 3000 RPM.






If greater than 15 mm-Hg (8 H2O) refer to Engine.






Recommended Procedure

Note: Do not plug hole on Crankcase Pressure Test Adapter 303-758 or equivalent.

Make sure the engine is at operating temperature. A cold engine gives higher readings. Remove the ducting to the turbocharger inlet pipe and remove the inlet pipe and elbow that connects to the breather box. Block the outlet at the valve cover with the cap provided in DSL ENG Pressure Test Kit 014-00761 or equivalent. Install a protective screen over the turbocharger inlet.

Install the Crankcase Pressure Test Adapter 303-758 or equivalent in the oil fill cap hole.

Plumb to the Magnehelic gauge (part of DSL ENG Pressure Test Kit 014-00761 or equivalent) in the gauge block. Make sure the Magnehelic gauge (part of DSL ENG Pressure Test Kit 014-00761 or equivalent) has been zeroed.

Start the engine and operate at 3000 RPM. Hold for 30 seconds minimum and take a stabilized reading. Do not block the hole at the top of the restrictor tool.

Possible Causes:

^ Broken or worn compression rings Polished cylinder bores
^ Leaking or bent valves

Inspect the air induction system. If the air induction system allows dirt to enter the cylinders it will quickly dust the engine causing high crankcase pressure.

Tools Required:

^ Crankcase Pressure Test Adapter 303-758 or equivalent
^ Magnehelic� gauge (part of DSL ENG Pressure Test Kit 014-00761 or equivalent)
^ Protective screen
^ Hose
^ Screw clamps