Engine Compression: Notes
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 1999 Mercury Villager, 1999 Mercury Mountaineer, 1999 Lincoln Navigator, 1999 Ford Windstar, and 1999 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
Check engine compression with engine at normal operating temperature, all glow (diesel) or spark plugs (gasoline) removed (on dual plugs, remove exhaust side only), and throttle wide open. Ensure crankcase is full and oil is of correct viscosity. With compression gauge installed, use remote starter switch to crank engine.
Crank engine at least 5 revolutions, and record highest reading. Repeat procedure for all cylinders, using approximately same number of revolutions. Lowest compression reading should not be less than 75 percent of highest compression reading. No cylinder compression reading should be less than 100 psi (7 kg/cm2 ).