OIL CONSUMPTION-DOHC ENGINES OR CARBON BUILDUP ON SOHC ENG.. Saturn Saturn 1991

For 1990-2009 cars

# OIL CONSUMPTION-DOHC ENGINES OR CARBON BUILDUP ON SOHC ENG.

#### SUBJECT: Oil Consumption on DOHC Engines or Carbon Buildup on SOHC Engines (Replace Valve Seals)

Due to addition of vehicle identification number (VIN) breakpoints, this bulletin supercedes Technical Information Bulletin No. 92-T-14A, which should be discarded. MODELS AFFECTED: All 1991 and 1992 Saturns built before, and including VIN NZ241997 with SOHC (LKO) engines and VIN NZ237282 with DOHC (LLO) engines.

#### CONDITION:

The DOHC engine may have higher than normal oil consumption (greater than 0.95L [1 qt.] in 3218 km [2000 miles]). The SOHC engine may have a stumble on deceleration or a misfiring cylinder while driving. Oil consumption may also be noticed on the SOHC engine.

#### CAUSE:

Valve stem seals may be worn, allowing oil to leak down the valve stem into the cylinder. On DOHC engines this condition will most likely lead to a concern of oil consumption. On SOHC engines, this condition may cause carbon buildup within the cylinders, resulting in various driveability complaints such as miss or stumble.

CORRECTIVE ACTION: On DOHC engines, perform an oil consumption verification test and replace valve seals if required. On SOHC engines, verify operation of ignition and engine control systems, remove carbon from valves and cylinders and replace valve seals.

#### IMPORTANT: For further information on oil consumption, refer to "Technical Information Bulletin 94-T-59."

#### PROCEDURE:

DOHC/SOHC Engines when the concern is higher than normal oil consumption

o Check for external oil leakage.

o Check fresh air hose and PCV valve for higher than normal oil pullover.

o Verify oil consumption by performing an oil consumption test as follows:

1. Change oil and oil filter. (3.8 liters [4 quarts] of oil are required to properly fill the crankcase).

2. Start engine and bring up to normal operating temperature 97 degrees - 100 degrees Celsius (197 degrees - 212 degrees Fahrenheit).

3. Park vehicle on level ground and wait a minimum of five minutes after engine is shut off. Check engine oil level, make sure it's at the FULL mark on the dipstick.

4. Mark dipstick with a scribe if not exactly at FULL mark.

5. Record the vehicle's mileafge, date of oil change and exact location of oil level on the Customer Service Order.

6. Have the customer check the engine oil leel at each fuel fill and return the vehicle if the oil level is at the "ADD" mark. If the oil level remains in the cross-hatch area, have the customer continue operating the vehicle for a minimum of 3218 km (2000 miles) before returning the vehicle for final oil consumption verification.

o If the engine is using more than 0.95L (1 qt.) per 3218 km (2000 miles), based on the oil consumption verification test, perform an engine cylinder compression test as outlined in the "Engine Mechanical Service Manual."

- If engine cylinder compression is found to be within acceptable limits, replace the valve stem seals.

- If engine cylinder compression is found to be not within acceptable limits, perform the required repairs according to information in the "Engine Mechanical Service Manual."

SOHC Engine: When the concern is stumble on deceleration or a misfiring cylinder while driving

o Verify that the ignition system and engine controls are operating correctly. Refer to the "Electronic Engine Controls Service Manual" for proper test procedures.

o Using GM Top Engine Cleaner (or equivalent), remove carbon from the valves and cylinders per cleaner manufacturer's instructions.

o Replace the valve seals.

Valve Seal Replacement

Valve seals can be replaced on both engines without removing the cylinder head or front cover. For service procedures, refer to the appropriate "Valve Spring and Stem Seal Replacement In-Vehicle" section (depending on engine type), in the "Engine Mechanical Service Manual."

#### NOTE: On the DOHC engine, always remove the hydraulic lifters immediately after each camshaft is removed. Removing the lifters from the cylinder head immediately after camshaft removal prevents the lifters from being filled with oil or pumped up. If the lifters are not removed, the engine may have to sit for several hours after the camshafts are installed, allowing the lifters to bleed down.

Four service tools are required to replace the valve stem seals.

o SA9127E, Universal Pressure Test Kit. Adapters from the kit are used to pressurize the combustion chamber and hold the valves closed when replacing the valve stem seals.

o SA9122E, DOHC Camshaft Tool. This tool is used to hold camshafts in place on the DOHC engine when removing lifters, valve spring cap locks, valve springs and valve stem seals.

#### NOTICE: Do not use afermarket valve spring remover and installation tools as lifter bore and/or valve stem damage may occur.

o SA9124E, Universal Valve Step Spring Compressor. This tool is used to remove valve spring cap locks.

o SA9102E, Valve Seal Removal Tool. This tool is used to remove and replace valve seals.

Once the valve stem seals are removed, inspect the valve stem for retainer lock damage to the valve stem during disassembly, scratches, scoring or scuffing. If the valve stem is damaged, the cylinder head will have to be removed and the valve replaced.

If the condition is acceptable, the valve guide and stem must be cleaned and lubricated with engine oil before installing a new valve seal.

#### NOTICE: The valve seal's sealing lip is usually damaged by the valve stem lock grooves when removed. If a seal is removed for any reason, the seal must be discarded and a new one installed. The valve stem must be lubricated with clean engine oil prior to installing the valve seal. After the seal is installed, the valve stem and seal must again be lubricated with clean engine oil.

After the new valve seals are installed, change the engine oil and filter, warm-up the engine and check for oil leaks. Ask the customer to continue monitoring the oil level, following the guidelines found in the "Maintenance Schedule" section labeled "Scheduled Maintenance Services" of the "Owner's Handbook." The Owner's Handbook recommends the oil level be checked at each fuel fill.

PARTS REQUIREMENTS: 21000872 Filter Asm-Oil 21006516 Seal Asm - Valve Stem OR, 8 - SOHC, 16 - DOHC

CLAIM INFORMATION: To receive credit for this repair, submit a claim through the Saturn Dealer System as follows:

Labor Case Operation Type Description Code Time ---- ----------- --------- ---- VW Bulletin-Base Time (Includes all inspections, replace all valve seals, change engine oil and filter) SOHC T9573 2.8 hrs DOHC T9573 4.5 hrs

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.