GM Service Manual Online
For 1990-2009 cars only

Engine Oil Caterpillar Diesel Engine

See the Caterpillar® Operation & Maintenance Manual for information on oil quality and viscosities as well as the temperature range chart.

Engine Oil Gasoline Engine


Object Number: 808323  Size: A1

If the low oil light appears on the instrument cluster, check the engine oil level right away.

For more information, see Low Oil Level Light . You should check the engine oil level regularly; this is an added reminder.

Checking Engine Oil

It is a good idea to check the engine oil every time you get fuel. In order to get an accurate reading, the oil must be warm and the vehicle must be on level ground.


Object Number: 829910  Size: A2

The engine oil dipstick is located in the engine compartment on the driver's side of the vehicle.

  1. Turn off the engine and give the oil several minutes to drain back into the oil pan. If you do not do this, the oil dipstick might not show the actual level.
  2. Pull out the dipstick and clean it with a paper towel or cloth, then push it back in all the way. Remove it again, keeping the tip down, and check the level.

When to Add Engine Oil


Object Number: 829813  Size: B2

If the oil is below the cross-hatched area at the tip of the dipstick, add at least one quart/liter of the recommended oil. This section explains what kind of oil to use. For engine oil crankcase capacity, see Capacities and Specifications .

Notice: Do not add too much oil. If the engine has so much oil that the oil level gets above the cross-hatched area that shows the proper operating range, the engine could be damaged.


Object Number: 824596  Size: A2

The engine oil fill cap is located near the engine oil dipstick in the engine compartment, on the driver's side of the vehicle.

Add enough oil to put the level somewhere in the proper operating range in the cross-hatched area. Push the dipstick all the way back in when you are through.

What Kind of Engine Oil to Use

Look for three things:


Object Number: 1501606  Size: B4
    • GM6094M
        Use only an oil that meets GM Standard GM6094M.
    • SAE 5W-30
        SAE 5W-30 is best for the vehicle. If you are in an area of extreme cold, where the temperature falls below -20°F (-29°C), use either an SAE 5W-30 synthetic oil or an SAE 0W-30 oil. Both provide easier cold starting and better protection for the engine at extremely low temperatures. These numbers on an oil container show its viscosity, or thickness. Do not use other viscosity oils such as SAE 20W-50.
    • American Petroleum Institute (API) starburst symbol

Object Number: 808500  Size: A2

Oils meeting these requirements should have the starburst symbol on the container. This symbol indicates that the oil has been certified by the American Petroleum Institute (API).

Notice: Use only engine oil identified as meeting GM Standard GM6094M and showing 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 vehicle warranty.

Engine Oil Additives

Do not add anything to the oil. The recommended oils with the API service symbol are all you need for good performance and engine protection.

Engine Oil DURAMAX Diesel

Checking Engine Oil

It is a good idea to check the engine oil level every time you get fuel.


Object Number: 829910  Size: A2

The engine oil dipstick is located in the engine compartment on the driver's side of the vehicle.

In order to get an accurate reading, the engine should be at normal operating temperature, so that the oil is warm, and the vehicle must be on level ground.

  1. If the engine is at normal operating temperature and the oil is warm, turn off the engine and allow at least five minutes for the oil to drain back into the oil pan. If you do not do this, the oil dipstick might not show the actual level.
  2. If the engine has not been run long enough to bring it up to normal operating temperature and the oil is cool, turn off the engine and allow 30 minutes for the oil to drain back into the oil pan. If you do not do this, the oil dipstick might not show the actual level.

  3. Pull out the dipstick and clean it with a paper towel or a cloth, then push it back in all the way.
  4. Remove the dipstick again, keeping the tip down, and check the oil level.

6.6L V8 (LLY) Engine


Object Number: 1284453  Size: B1

7.8L L6 (LG4) Engine


Object Number: 815651  Size: B2

When to Add Engine Oil

If the oil is below the cross-hatched area at the tip of the dipstick for the 6.6L V8 (LLY) engine, you will need to add at least two quarts/liters of oil. If the oil is below the lower hole at the tip of the dipstick for the 7.8L L6 (LG4) engine, you will need to add at least one quart/liter of oil. But you must use the right kind. This section explains what kind of oil to use. For engine oil crankcase capacity, see Capacities and Specifications .

Notice: Do not add too much oil. If the engine has so much oil that the oil level gets above the cross-hatched area for the 6.6L V8 (LLY) engine or above the upper hole that shows the proper operating range for the 7.8L L6 (LG4) engine, the engine could be damaged.


Object Number: 1284396  Size: A2

Add oil at the engine oil fill cap in the engine compartment. Install and fully tighten the fill cap when you are through.

Be sure to add enough oil to put the level somewhere in the proper operating range. Push the dipstick all the way back in when you are through.

What Kind of Engine Oil to Use

Look for these two things:

    • CI-4 or CH-4
        Oils designated as API CI-4 or CH-4 are recommended for your vehicle. The CI-4 or CH-4 designations may appear either alone, together, or in combination with other API designations, such as API CI-4/SL.
        These letters show American Petroleum Institute (API) levels of quality.

Notice: Use only engine oils that have one of these designations, CI-4 or CH-4, for the Duramax® diesel engine. Failure to use the recommended oils can result in engine damage not covered by your warranty.


Object Number: 1551807  Size: B5
    • SAE 15W-40
        As shown in the viscosity chart, SAE 15W-40 is best for your vehicle. However, you can use SAE 10W-30 at temperatures above 0°F (-18°C). When it is very cold, below 0°F (-18°C), you should use SAE 5W-40 to improve cold starting. 5W-40 is not recommended for use at high temperatures, above 100°F (38°C).
        These numbers on the oil container show its viscosity, or thickness. Do not use other viscosity oils such as SAE 10W-40 or SAE 20W-50.

Object Number: 865952  Size: A2

This doughnut-shaped logo (symbol) is used on most oil containers to help you select the correct oil. It means that the oil has been certified by the American Petroleum Institute.

You should look for this on the oil container, and use only those oils that display this logo.

GM Goodwrench® oil of the recommended viscosity grades meets all the requirements for your vehicle.

Engine Oil Additives

Do not add anything to the oil. The recommended oils with the API service symbol are all you will need for good performance and engine protection.

When to Change Engine Oil (Vehicles Without the Engine Oil Life System)

If you have the 6.6L V8 (LLY) Engine: Change engine oil and filter every 15,000 miles (24 000 km), or every 12 months, or every 750 hours of engine operation, whichever occurs first. If you have the 7.8L V6 (LG4) Engine: Change engine oil and filter every 12,000 miles (20 000 km), or every 12 months, or every 600 hours of engine operation, whichever occurs first. See Scheduled Maintenance .