NO: 09-18-92
SUBJECT: Excessive Oil Consumption 3.0L MMC Engine
DATE: Jan. 13, 1993
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 09-18-92 WHICH SHOULD BE REMOVED FROM YOUR FILES.
DISCUSSION:
Engines built since 11/15/91 (build code BDL7.067) have snap rings installed the exhaust valve guides. Engines built since 10/2/92 (build code BDL7.416) have improved intake and exhaust valve stem seals in addition to the snap rings on the exhaust valve guides. The build code label is located on the intake plenum.
SYMPTOM/CONDITION:
Observed oil smoke in the exhaust at idle or during deceleration (conditions causing high intake manifold vacuum. Excessive oil consumption is more than one quart per 1,000 miles on vehicles with less than 50,000 miles or more than one quart per 750 miles on vehicles with more than 50,000 miles.
DIAGNOSIS:
Verify the PCV system is functioning properly and engine compression is within specifications. Refer to the appropriate technical service manual for test procedures and specifications. If the PCV system and engine compression are within specification, perform the repair procedure below.
PARTS REQUIRED:
Quantity
Description
Part No.
1
Parts kit
MD303116
Kit consists of:
6
Snap Ring
MD185547
12
Seal, valve stem
MD197467
AR
Head, Cylinder
MD182211
AR
Gasket Set, Engine Upper
MD972034
SPECIAL TOOLS REQUIRED:
Groove Cutter
MD998790
Blade, Groove Cutter Replacement
MD998791
Valve Spring Compressor
MD998772A
Valve Stem Seal Installer
MD998729
Valve Guide Installer
MD998115
REPAIR PROCEDURE:
This bulletin involves installing snap rings on the exhaust valve guides and replacing all of the valve stem seals or cylinder head replacement as determined by inspection.
Remove the intake plenum and manifold.
Remove the rocker cover, rocker shaft and cam bearing cap assembly on the forward bank using the procedure in the appropriate technical service manual.
Remove one of the cam journal caps from the assembly and reinstall on the head. This will prevent the cam from possibly coming out of the journals when the engine is rotated later.
Check front bank cylinders in #4, #2, then #6 sequence.
NOTE: IF A VALVE GUIDE CAN BE MOVED WITH FINGER PRESSURE, REPLACE THE CYLINDER HEAD.
Remove the spark plug and apply compressed air to the cylinder to prevent valve dropping. Use special tool MD998772A to remove the intake and exhaust valve locks, the valve spring retainer, valve spring and valve spring seat.
Remove the valve stem seals.
Using the height gauge that is integrated into the Groove Cutter (Special tool MD998790), measure the distance between the top of the exhaust valve guide and the top of the valve guide boss on the cylinder head (refer to illustrations of Figure 1). If the distance is .335" (8.5mm) or less the cylinder head will have to be removed for repair, perform PROCEDURE B. If the distance is .335" (8.5mm) or more, perform PROCEDURE A.
Repeat steps 2 through 7 for the rear bank. Do the cylinders in #3, #1, and #5 sequence.
PROCEDURE A Snap Ring Installation and Valve Stem Seal Replacement (On the Vehicle)
Using the groove cutter (Special tool MD998790), make a groove in the exhaust valve guide (refer to Figure 2 and Figure 3 ).
Install the special tool on the exhaust valve guide.
Turn the tool clockwise until the force required to turn the tool suddenly decreases.
Remove the tool.
Using a magnet and shop towel, remove the cuttings from the cylinder head.
Install a snap ring in the groove cut in the exhaust valve guide (refer to Figure 4).
Check the exhaust valve guide height with the .453" (11.5mm) side of special tool MD998790 and a .040" (1mm) feeler gauge. If the measurement is .413 (10.5mm) or more (feeler gauge will not fit between special tool and top of valve guide) install the valve spring seat. Install all of the intake valve spring seats.
Install new valve stem seals on the intake and exhaust valve guides using special tool MD998729.
Reinstall the valve spring assemblies including the valve spring seats if not already installed step 4 of PROCEDURE A.
Return to step 4 of the PROCEDURE A and proceed to the next cylinder in sequence unless, all exhaust valve guide snap rings have been installed and all valve stem seals replaced on this head.
Reinstall the rocker shaft assembly, camshaft bearing caps, rocker cover and spark plugs. Return to step 8 of the REPAIR PROCEDURE unless this step completed the repair to both heads.
Using the procedures in the appropriate service manual, reassemble the engine.
PROCEDURE B Valve Guide Height Correction, Snap Ring Installation
Remove the cylinder head using the procedure in the appropriate service manual.
Remove all of the valve spring assemblies and valves. Mark the valves so they can be returned to their original position at reassembly.
Remove all of the valve stem seals.
Check the height on any exhaust valve guides not already checked to determine if height correction will be required on more than one guide.
Remove any carbon from the bottom of the exhaust valve guides that need to have their height corrected, especially the face that special tool MD998115 will contact.
Using special tool MD998115 and hammer, carefully drive the exhaust valve guides from the combustion chamber side to provide a valve guide height from the top of the guide to the top of the boss for the valve guide on the cylinder head of .453" (11.5mm). Check the distance using the height gauge that is integrated into the groove cutter (Special tool MD998790). Refer to Figure 1 and Figure 5. If the valve guide is driven up too far and the valve guide height exceeds .453" (11.5mm) use special tool MD998115 to drive the valve guide from the rocker shaft side of the head until the .453" (11.5mm) height is achieved.
Inspect the valve seats using the prussian blue procedure in the appropriate service manual.
Using the groove cutter (Special tool MD998790), make a groove on all of the exhaust valve guides (refer to Figure 2 and Figure 3).
Install the special tool on the exhaust valve guide.
Turn the tool clockwise until the force required to turn the tool suddenly decreases.
Remove the tool.
Use a magnet and shop towel or wash the cylinder head to remove the cuttings.
Install a snap ring on each exhaust valve guide (refer to Figure 4).
Check the exhaust valve guide height with the .453" (11.5mm) side of special tool MD998790 and a .040" (1mm) feeler gauge. If the measurement is .413 (10.5mm) or more (feeler gauge will not fit between special tool and top of valve guide) install the valve spring seat. Install all of the intake valve spring seats.
Install new valve stem seals on the intake and exhaust valve guides using special tool MD998729.
Reassemble the cylinder head and install using the procedure in the appropriate service manual. Return to step 8 of the REPAIR PROCEDURE unless this step completed the repair to both heads.
Using the procedures in the appropriate service manual, reassemble the engine.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No.
Description
Time
09-35-01-92
Repair Valve Guides and Replace Seals, Both Heads on Vehicle
4.1 Hrs.
09-35-01-93
Repair Rear Head On Vehicle - Remove Front Head and repair or Replace Head as Required
6.0 Hrs.
09-35-01-94
Repair Front Head On Vehicle - Remove Rear Head and Repair or Replace Head as Required
6.2 Hrs.
09-35-01-95
Remove Both Heads and Repair or Replace Head as Required
6.4 Hrs.
FAILURE CODE:
Code
Description
70
Oil Consumption