Cylinder Head Disassemble (LY7)

Special Tools

• EN-46116:  Valve Stem Seal Remover/Installer
• EN-46117:  Valve Stem Key Remover/Installer
• EN-46119:  Off-Vehicle Valve Spring Compressor Adapter
• EN-46122:  Camshaft Position Actuator Check-Ball Valve Remover/Installer
• J-8062:  Valve Spring Compressor - Head Off

  For equivalent regional tools, refer to Special Tools .

Fig 1: Identifying Engine Coolant Temperature (ECT) Sensor
Courtesy of GENERAL MOTORS CORP.
1. Remove the engine coolant temperature (ECT) sensor.
Fig 2: Identifying Spark Plugs
Courtesy of GENERAL MOTORS CORP.
2. Remove the spark plugs.
Fig 3: Loosening Valve Keepers
Courtesy of GENERAL MOTORS CORP.
NOTE: Ensure valve heads will not contact anything during the following step in order to avoid bending or damage.
3. Using an appropriately sized deep socket and a plastic hammer, lightly tap on the valve spring retainer to loosen the valve keepers.
Fig 4: Identifying J 8062 & EN 46119
Courtesy of GENERAL MOTORS CORP.
WARNING: Compressed valve springs have high tension against the valve spring compressor. Valve springs that are not properly compressed by or released from the valve spring compressor can be ejected from the valve spring compressor with intense force. Use care when compressing or releasing the valve spring with the valve spring compressor and when removing or installing the valve stem keys. Failing to use care may cause personal injury.
CAUTION: Do not compress the valve springs to less than 24.0 mm (0.943 in). Contact between the valve spring retainer and the valve stem oil seal can cause potential valve stem oil seal damage.
4. Compress the valve spring using the J-8062:  compressor - head off and the EN-46119:  adapter.
Fig 5: View Of EN 46117
Courtesy of GENERAL MOTORS CORP.
5. Use the magnet of the EN-46117:  key remover/installer in order to remove the valve keepers.
6. Remove the valve spring compressor and the adapter.
Fig 6: Identifying Valve Spring & Retainer
Courtesy of GENERAL MOTORS CORP.
7. Remove the valve spring retainer.
8. Remove the valve spring.
Fig 7: View Of Valve
Courtesy of GENERAL MOTORS CORP.
9. Remove the valve.
Fig 8: View Of Valve Stem Oil Seals With EN 46116
Courtesy of GENERAL MOTORS CORP.
NOTE: NEVER reuse a valve stem oil seal.
10. Remove the valve stem oil seal using the EN-46116:  seal remover/installer and discard.
11. Repeat these procedures for the remaining valves.
Fig 9: Cylinder Head Oil Gallery Expansion Plugs
Courtesy of GENERAL MOTORS CORP.
12. Remove the cylinder head oil gallery expansion plugs.
Fig 10: Locating Cylinder Head Coolant Threaded Plugs
Courtesy of GENERAL MOTORS CORP.
13. Remove the cylinder head coolant threaded plugs.
Fig 11: View Of Camshaft Position Actuator Oil Feed Check Valve
Courtesy of GENERAL MOTORS CORP.
14. Inspect the camshaft position actuator oil feed check valves. Damaged, restricted or clogged check valves must be replaced.
Fig 12: Drilling Out Top Portion Of Check Valve
Courtesy of GENERAL MOTORS CORP.
15. Place cylinder head on firm surface with check valves (1) facing up. Protect all cylinder head components and machined surfaces.
16. Using drill bit EN-46122-3, drill out top portion of check valve to expose internal check ball.
Fig 13: Identifying Check Ball & Check Ball Spring
Courtesy of GENERAL MOTORS CORP.
17. Remove check ball (1) and check ball spring (2) from inside of check valve.
Fig 14: Drilling Remainder Of Check Valve Sleeve
Courtesy of GENERAL MOTORS CORP.
18. Continue drilling remainder of check valve sleeve to a depth of approximately 19 mm (0.75 in) (a) by placing tape on drill bit as a depth gauge. It is not necessary or desirable to drill completely through the bottom of the check valve.
Fig 15: Tapping Drilled Out Portion Of Check Valve
Courtesy of GENERAL MOTORS CORP.
19. Lubricate tap EN-46122-4 with lubricant included in EN-46122:  remover/installer. Tap drilled out portion of check valve (1) remaining in cylinder head. Tap to full depth possible until tap bottoms out in head.
Fig 16: View of Bolt, Nut, Washers and Collar EN-46122--2
Courtesy of GENERAL MOTORS CORP.
20. Assemble bolt, nut, washers, and collar EN-46122-2 (1) as shown. Position collar with slightly-larger inside diameter DOWN toward the cylinder head.
21. Screw bolt by hand fully down into threaded check valve sleeve, then lightly tighten nut against washer.
Fig 17: View Of Check Valve Sleeve & Cylinder Head
Courtesy of GENERAL MOTORS CORP.
22. Hold bolt with one wrench, and use another to tighten the nut until the check valve sleeve (1) is removed from the cylinder head.
23. Clean check valve bore and related passages thoroughly to remove any drilling chips or other debris.