Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
use of Plastigage:
1. Remove oil film from surface to be checked. Plastigage is soluble in oil.
Placement Of Plastigage In Bearing Shell
2. Place a piece of Plastigage across the entire width of the bearing cap shell. Position the Plastigage approximately 6.35 mm (1/4 in.) off center and
away from the oil holes. In addition, suspect areas can be checked by placing the Plastigage in the suspect area.
3. The crankshaft must be turned until the connecting rod to be checked starts moving toward the top of the engine. Only then should the rod cap with
Plastigage in place be assembled. Tighten the rod cap nuts to required torque. DO NOT rotate the crankshaft or the Plastigage may be
smeared, giving inaccurate results.
Clearance Measurement
4. Remove the bearing cap and compare the width of the flattened Plastigage with the scale provided on the package. Plastigage generally comes in 2
scales (one scale is in inches and the other is a metric scale). Locate the band closest to the same width. This band shows the amount of clearance.
Differences in readings between the ends indicate the amount of taper present. Record all readings taken.
5. Plastigage is available in a variety of clearance ranges. The 0.025-0.076 mm (0.001-0.003 in.) range is usually the most appropriate for checking
engine bearing clearances.
