GM Service Manual Online
For 1990-2009 cars only

For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .

The following text and illustrations describe the details of the required scheduled maintenance services.

For information on the proper fluids and lubricants to use, refer to Fluid and Lubricant Recommendations .

Engine Oil and Oil Filter Change

Replace the engine oil and the engine oil filter.

    • For the 3.1 (LG8) engine, refer to Engine Oil and Oil Filter Replacement in Engine Mechanical.
    • For the 3.8 (L36) or 3.8 (L67) engine, refer to Engine Oil and Oil Filter Replacement in Engine Mechanical.

Engine Oil Quality United States and Canada

Notice: Use only engine oil with the American Petroleum Institute Certified for Gasoline Engines starburst symbol. Failure to use the recommended oil can result in engine damage not covered by the warranty.


Object Number: 65538  Size: SH

The STARBURST symbol indicates that the oil has been certified by the American Petroleum Institute (API). Do not use any oil which does not carry the STARBURST symbol.

Engine Oil Viscosity, United States and Canada

Notice: Using oils of any viscosity other than those recommended could result in engine damage. When choosing an oil, consider the range of temperatures the vehicle will be operated in before the next oil change. Then, select the recommended oil viscosity.

Oil Viscosity Recommendation for 3100 LG8


Object Number: 65536  Size: MH
    • For the 3100 LG8 (VIN J) engine, SAE 5W-30 is the recommended engine oil viscosity. Engine oil viscosity (thickness) has an effect on the fuel economy and the cold-weather operation (engine starting and oil flow). Lower viscosity engine oils can provide better fuel economy and cold-weather performance. However, higher temperature weather conditions require higher viscosity engine oils for satisfactory lubrication. When the temperature is consistently above -18°C (0°F), 10W-30 may be used. SAE 20W-50 or oils of other viscosity rating or quality designations are NOT recommended for use in any GMC vehicle at any time.

Oil Viscosity Recommendation for 3800 L36 and 3800 L67


Object Number: 196359  Size: MH
    • For the 3800 L36 or a 3800 L67 engine, SAE 10W-30 is the recommended engine oil viscosity. Engine oil viscosity (thickness) has an effect on the fuel economy and the cold-weather operation (engine starting and oil flow). Lower viscosity engine oils can provide better fuel economy and cold-weather performance. However, higher temperature weather conditions require higher viscosity engine oils for satisfactory lubrication. When the temperature is consistently lower than 16°C (60°F), 5W-30 may be used. SAE 20W-50 or oils of other viscosity rating or quality designations are NOT recommended for use in any GMC vehicle at any time.

Engine Oil Quality and Viscosity (Other Than The United States and Canada)


Object Number: 404726  Size: MF

Notice: Using oils of any viscosity other than those recommended could result in engine damage. When choosing an oil, consider the range of temperatures the vehicle will be operated in before the next oil change. Then, select the recommended oil viscosity.

Important: When adding to, or changing the engine oil, use ONLY oils of the proper quality. In countries other than the United States and Canada, it may be difficult to find engine oils that display the API STARBURST symbol certifying the oil is for use in gasoline engines. If you are unable to find engine oils displaying the API STARBURST symbol, use engine oils that meet API Service SJ and/or ACEA A1-96, ACEA A2-96, or ACEA A3-96 requirements as shown in the chart above.

Tire and Wheel Inspection and Rotation


Object Number: 105088  Size: SH

Check the tires for abnormal wear or damage. Rotate the tires to equalize the wear and obtain maximum tire life. Irregular or premature wear may indicate a problem. Refer to Tire Rotation in Suspension.

If irregular or premature tire wear exists, refer to Suspension General Diagnosis in Suspension General Diagnosis.

Accessory Drive Belt Inspection

Inspect the drive belt according to the maintenance schedule intervals.

For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .

Inspect the accessory drive belts for the following:

    • Cracks
    • Fraying
    • Wear
    • Proper tension

Replace as needed. (Belts can have many small cracks in individual ribs without affecting the performance.) For drive belt replacement for the 3.1(LG8) engine, refer to Drive Belt Replacement in Engine Mechanical.

For drive belt replacement for the 3.8 (L36 or L67) engine, refer to Drive Belt Replacement in Engine Mechanical.

Brake System Inspection

Inspect brake lines and hoses for proper hook-up binding, leaks, cracks or chafing. Refer to Brake Hose Inspection in Hydraulic Brakes. Inspect disc brake pads for wear. Refer to Brake Pad Inspection in Disc Brakes. Inspect the rotors for poor surface condition. Inspect other brake system components, including the brake calipers, the parking brake, etc. Check the parking brake adjustment.

The brakes may need to be inspected more often if the customer's driving habits or conditions result in frequent braking.

Automatic Transaxle Service

Change the transaxle fluid and the transaxle fluid filter according to the maintenance schedule intervals. Use the proper fluid. For the fluid and filter changing procedure, refer to Automatic Transmission Fluid Filter and Seal Replacement .

For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .

Spark Plug Replacement

Replace the spark plugs according to the maintenance schedule intervals. For the spark plug replacement procedure, refer to Spark Plug Replacement in Engine Electrical.

For information on the correct type of spark plug, refer to Maintenance Items .

For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .

Spark Plug Wire Inspection

Clean the spark plug wires and inspect for burns, cracks or other damage. Ensure that the fit between the spark plug wire boots at the spark plugs and at the coils is snug. Replace the spark plug wires as needed. Refer to Spark Plug Wire Harness Replacement in Engine Electrical.

Air Cleaner Filter Inspection and Replacement

Replace the air cleaner filter according to the maintenance schedule intervals. For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .

For information on the correct type of air cleaner filter, refer to Maintenance Items

For air cleaner filter replacement procedure, refer to Air Filter Element Replacement in 3.1 L Engine Controls.

Refer to Air Cleaner Element Replacement in 3.8 L Engine Controls.

Passenger Compartment Air Filter Replacement

Replace the passenger compartment air filter. Refer to Passenger Compartment Air Filter Replacement in HVAC Systems.

Supercharger Oil Level Inspection

Inspect the supercharger oil level and add oil if necessary. Refer to Supercharger Oil Level Inspection

Cooling System Service

Drain, flush and refill the cooling system with new coolant. Refer to Cooling System Draining and Filling in Engine Cooling.

For time and/or mileage intervals of scheduled maintenance items, refer to Maintenance Schedule .