Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2002 Jeep TJ (CANADA) L4-2.5LFACTORY OEM SERVICE PROCEDURE
Piston, Engine
PISTON
Weight (Less Pin) 417 to 429 grams (14.7 to 15.1 oz.)
Compression Height 40.61 to 40.72 mm (1.599 to 1.603 inch)
Piston to Bore Clearance 0.018 to 0.038 mm (0.0008 to 0.0015 inch)
Piston Ring Groove Height
Compression Rings 1.530 to 1.555 mm (0.0602 to 0.0612 inch)
Oil Control Ring 4.035 to 4.060 mm (0.1589 to 0.1598 inch)
Piston Ring Groove Diameter
Compression Ring #1 88.39 to 88.65 mm (3.48 to 3.49 inch)
Compression Ring #2 87.63 to 87.88 mm (89.66 to 89.92 inch)
Oil Control Ring 89.66 to 89.92 mm (3.53 to 3.54 inch)
Piston Pin
Bore Diameter 23.650 to 23.658 mm (0.9312 to 0.9315 inch)
Pin Diameter 23.637 to 23.640 mm (0.9306 to 0.9307 inch)
Piston to Pin Clearance 0.0102 to 0.0208 mm (0.0005 to 0.0009 inch)
Weight (Less Pin) 417 to 429 grams (14.7 to 15.1 oz.)
Compression Height 40.61 to 40.72 mm (1.599 to 1.603 inch)
Piston to Bore Clearance 0.018 to 0.038 mm (0.0008 to 0.0015 inch)
Piston Ring Groove Height
Compression Rings 1.530 to 1.555 mm (0.0602 to 0.0612 inch)
Oil Control Ring 4.035 to 4.060 mm (0.1589 to 0.1598 inch)
Piston Ring Groove Diameter
Compression Ring #1 88.39 to 88.65 mm (3.48 to 3.49 inch)
Compression Ring #2 87.63 to 87.88 mm (89.66 to 89.92 inch)
Oil Control Ring 89.66 to 89.92 mm (3.53 to 3.54 inch)
Piston Pin
Bore Diameter 23.650 to 23.658 mm (0.9312 to 0.9315 inch)
Pin Diameter 23.637 to 23.640 mm (0.9306 to 0.9307 inch)
Piston to Pin Clearance 0.0102 to 0.0208 mm (0.0005 to 0.0009 inch)
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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