Cold Engine - Lifter Ticking Noise
File In Section: 6 - EngineBulletin No.: 57-61-09
Date: November, 1995
Subject:
Cold Engine Lifter Tick Noise (Modify Camshaft Thrust Plate Oiling)
Models:
1991-94 Chevrolet Lumina
1995 Chevrolet Lumina, Monte Carlo - Built Prior to VIN Breakpoint S9148603 1991-94 Oldsmobile Cutlass Supreme
1991-94 Pontiac Grand Prix
with 3.4L DOHC V6 Engine (VIN X - RPO LQ1)
Condition
Some owners may comment on a tick type noise on a cold engine. This noise will be present after a minimum of a 2 hour cold soak. The engine may be quiet on the initial start for approximately 30-60 seconds, then the tick will appear for 5-10 minutes and then goes away after the engine is warmed up. This tick noise will not be heard on a hot restart. This noise is not detrimental to the dependability or reliability of the engine.
Cause
Lifter tick noise is a function of oil temperature. Under cold conditions, high oil pressure fluctuations in the lifter gallery are unseating the internal lifter check ball which allows the lifter to momentarily collapse. Lifter gallery pressure fluctuations at low speed vary significantly with oil temperature. Thus, tick noise is dependent on the timing of a rapid oil pressure drop in the lifter gallery.
Correction
An Oiling Scheme Improvement Package has been developed. For engines produced after August 23, 1994 the improved system will have a camshaft which will not have the thrust plate groove 4 mm oiling hole. The cup plug in the camshaft will have a 2 mm hole to oil the thrust plate. By restricting the flow of oil from the lifter gallery with a 2 mm hole, it improves overhead oil pressure and dampens the oil pulsations of cold engine oil. The Oiling Scheme Improvement Package is available as a service repair kit, part number 12538687. The repairs involve eliminating the 4 mm thrust plate groove oil hole, installing a new cup plug with a 2 mm hole in the end of the camshafts and a thinner thrust plate (Figure 1).
The following service procedure is applicable to 1991-94 W cars with the 3.4L DOHC V6 Engine and 1995 Chevrolet Lumina, Monte Carlo built prior to VIN S9148603.
Remove or Disconnect
1. Negative battery cable.
2. Air cleaner.
3. Drain engine coolant.
4. Control cables from throttle body of upper intake.
5. Fuel rail cover.
6. PCV valve and vacuum line from throttle body, vacuum modulator line at intake manifold.
7. Heater hose at lower intake manifold.
8. Electrical connectors on TPS, EGR, evaporative emission canister purge solenoid, map.
9. EGR bolts.
10. EGR valve, set aside.
11. Fuel line bracket at throttle body of upper intake.
12. Loosen throttle body heater hose clamp at upper intake manifold heater hose clamp at upper intake manifold.
13. Bolts at vacuum source manifold assembly/map on upper intake manifold.
14. Rear bank spark plug wires.
15. Nuts at upper intake manifold support bracket.
16. Upper intake manifold bolts.
17. Upper intake manifold.
18. Cover intake runners with a shop towel.
CAM Carrier Thrust Plate Rear Cover
Right Side (Rear)
Remove or Disconnect
19. Cam carrier rear cover mounting bolt/screw.
20. Cam carrier rear cover and gasket.
21. Remove the cup plugs in the end of the camshafts by punching a hole in the plug using an awl. Insert a long screw into the hole and use a pry device against the screw head to remove the cup plug (Figure 2).
22. Remove the camshaft thrust plate.
23. Rotate engine so that the oil holes located in the thrust plate groove are facing up.
24. Fabricate a chip tray by folding a 1 x 5 piece of paper into a vee shape and insert into the end of each camshaft.
25. Drill both camshafts oil holes (located in the thrust plate groove with a number 21 drill (.1590) bit) (Figure 4).
26. Use a 10/32 tap and tap both oil holes to a depth of approximately 6 mm, or take the set screw and if using a tapered tap, place it on the untappered portion of the tap and mark the tap with a paint pencil. If using a bottoming tap, simply mark the tap the length of the set screw thus setting your depth (Figure 3). It is not necessary to tap the complete hole, for you want to leave a shoulder for the set screw to bottom against.
27. Emery cloth the thrust plate groove at the oil hole to remove any burrs.
28. Remove the chip trays, use a spray cleaner to remove excess debris and blow dry with air.
29. Red Loctite(R) (GM part number 12345493 or equivalent) both set screws and insert into the tapped oil holes.
30. Install the new cam thrust plate provided with the kit, tighten bolts to 10 N.m (89 lb in.).
Notice:
It is important that you clean all debris from the oil passage hole, failure to do so could result in a premature engine failure.
31. Install the new cup plugs provided with the kit into the end of the camshafts. One way of doing this is to place the cup plug onto a socket, use a pair of pliers to grip the socket and tap the socket with a hammer to set the cup plug. The plug will bottom out on a shoulder in the hole of the camshaft (Figure 5).
32. Install a new cover gasket provided with the kit, tighten bolts to 10 N.m (89 lb in.).
CAM Carrier Thrust Plate Rear Cover
Left Side (Front)
Remove or Disconnect
33. Upper radiator hose.
34. Exhaust crossover pipe.
35. Heater pipe assembly from coolant pump to upper intake manifold.
36. Thermostat housing.
37. Engine torque strut.
38. Engine lift support.
39. Cam carrier rear cover mounting bolt/screw.
40. Cam carrier rear cover and gasket.
41. Remove the cup plugs in the end of the camshafts by punching a hole in the plug using an awl. Insert a long screw into the hole and use a pry device against the screw head to remove the cup plug (Figure 2).
42. Remove the camshaft thrust plate.
43. Rotate engine so that the oil holes located in the thrust plate groove are facing up.
44. Fabricate a chip tray by folding a 1 x 5 piece of paper into a vee shape and insert into the end of each camshaft.
45. Drill both camshafts oil holes (located in the thrust plate groove with a number 21 drill (.1590) bit) (Figure 4).
46. Use a 10/32 tap and tap both oil holes to a depth of approximately 6 mm, or take the set screw and if using a tapered tap, place it on the untappered portion of the tap and mark the tap with a paint pencil. If using a bottoming tap, simply mark the tap the length of the set screw thus setting your depth (Figure 3). It is not necessary to tap the complete hole, for you want to leave a shoulder for the set screw to bottom against.
47. Emery cloth the thrust plate groove at the oil hole to remove any burrs.
48. Remove the chip trays, use a spray cleaner to remove excess debris and blow dry with air.
49. Red Loctite(R) (GM part number 12345493 or equivalent) both set screw and insert into the tapped oil holes.
50. Install the new cam thrust plate provided with the kit, tighten bolts to 10 N.m (89 lb in.).
Notice:
It is important that you clean all debris from the oil passage hole, failure to do so could result in a premature engine failure.
51. Install the new cup plugs provided with the kit into the end of the camshafts. One way of doing this is to place the cup plug onto a socket, use a pair of pliers to grip the socket and tap the socket with a hammer to set the cup plug. The plug will bottom out on a shoulder in the hole of the camshaft (Figure 5).
52. Install new cover gasket provided in kit and cover, tighten bolts to 10 N.m (89 lb in.).
Install or Connect
53. Engine lift support, tighten bolts to 70 N.m (52 lb ft).
54. Engine torque strut.
55. Thermostat housing to inlet manifold, bolts to housing with RTV sealer GM part number 1052366 or equivalent, tighten bolts to 25 N.m (18 lb ft).
56. Heater pipe assembly from coolant pump to upper intake manifold, tighten bolt to 11 N.m (92 lb in.) nut to 25 N.m (18 lb ft).
57. Exhaust crossover pipe, tighten nuts to 25 N.m (18 lb ft).
58. Upper radiator hose.
59. Upper intake manifold, gasket and 0 ring provided in kit.
60. Upper intake manifold bolts, tighten to 30 N.m (22 lb ft).
61. Nuts at upper intake manifold support bracket, tighten to 30 N.m (22 lb ft).
62. Rear bank spark plug wires.
63. Bolts at vacuum source manifold assembly/map on upper intake, tighten bolts to 5 N.m (45 lb in.).
64. Tighten throttle body heater hose clamp at upper intake.
65. Fuel line bracket at throttle body of upper intake.
66. EGR valve and gaskets provided in kit, tighten bolts to 27 N.m (20 lb ft).
67. Electrical connectors on TPS, EGR, evaporative emission canister purge solenoid, map.
68. PCV valve and vacuum line at throttle body of upper intake, vacuum modulator line at intake manifold.
69. Fuel rail cover, tighten bolts 10 N.m (89 lb in.).
70. Control cables at throttle body of upper intake.
71. Refill coolant (see Service Manual Section 6B).
72. Air cleaner.
73. Negative battery cable.
Part Information
Parts are expected to be available on November 13, 1995 from GMSPO.
Part Number Name Quantity
12538687 Repair Kit - Camshaft 1
The kit will consist of the parts as shown.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation Labor Time
J0032 3.3 hrs