Test 17: Crankcase Pressure Test: Purpose
WARNING: This page is about a different car, the 2003 Ford Pickup, 2003 Ford F550 Super Duty, 2003 Ford F450 Super Duty, 2003 Ford Excursion, and 2003 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
This test is performed to measure crankcase pressure. Crankcase pressure is an indication of how well cylinders are sealing.