Piston, Connecting Rod, and Bearings Cleaning and Inspection

WARNING: This page is about a different car, the 2002 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Bodily injury may occur if the cleaning solvent is inhaled or exposed to the skin.

Clean the piston and connecting rod in solvent.
CAUTION: Refer to SAFETY GLASSES CAUTION .
Dry the components with compressed air.
Clean the piston ring grooves with a suitable ring groove cleaning tool.
Clean the piston oil lubrication holes and slots.

Fig 1: Clean Piston & Connecting Rod
Courtesy of GENERAL MOTORS CORP.
Inspect the piston for the following conditions:
- Eroded areas (1) on top of the piston
- Scuffed or damaged skirt (2)
- Damage to the pin bore (3)
- Cracks in the piston ring lands, the piston skirt, or the pin bosses
- Piston ring grooves for nicks, burrs, or other warpage which may cause the piston ring to bind.
Inspect the piston for scoring, wear or other damage.

Fig 2: Inspect Piston
Courtesy of GENERAL MOTORS CORP.
To determine the piston-to bore clearance, use a micrometer and measure the piston pin.

Fig 3: Measure Piston Pin
Courtesy of GENERAL MOTORS CORP.
To determine the piston pin-to-bore clearance, use an inside micrometer and measure the piston pin bore.
To determine the piston pin-to-bore clearance, subtract the piston pin diameter from the piston pin bore diameter.

Fig 4: Measure Piston Pin Bore
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod for an out-of-round bearing bore.

Fig 5: Inspect Connecting Rod For Out-Of-Round Bearing Bore
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod for twisting.

Fig 6: Inspect Connecting Rod For Twisting
Courtesy of GENERAL MOTORS CORP.
Inspect the connecting rod cap bolts for stretch (compare to known good bolt) (1) is a stretched bolt, (2) is a new or good bolt.

Fig 7: Inspect Connecting Rod Cap Bolts For Stretch
Courtesy of GENERAL MOTORS CORP.