Fuel Specific Gravity Testing
Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5095235 Diesel Fuel American Petroleum Institute (API) Gravity Requirements
| Specification | No. 2 Diesel with up to 20% Bio-diesel | No. 2 Diesel | No. 1 Diesel | R99 Diesel |
|---|---|---|---|---|
| Specific Gravity | 34–38 | 35–39 | 40–44 | 47–51 |
Fuel Specific Gravity Test
- Fill a 1 liter (0.946 quart) container with a sample of fuel.
- Obtain a J 38641-B Diesel Fuel Quality Tester.
- Fill the hydrometer with the fuel sample by doing the following: 3.1. Squeeze the hydrometer bulb. 3.2. Submerse the hydrometer tip into the sample. 3.3. Release the bulb, allowing fuel to enter the glass tube until the fuel completely floats the glass bulb inside the tube. 3.4. Gently spin the hydrometer to relieve the surface tension of the fuel sample. Read the scale on the glass bulb at the point where the top of the fuel sample contacts the scale. This value will give an approximate fuel oil specific gravity. ⇒ If greater than 45 3.1. Place a 6–8 oz. Styrofoam cup in a glass container. 3.2. Using the fuel obtained in the Fuel Specific Gravity Test, measure out 100 ml of fuel sample. 3.3. Pour the sample into the Styrofoam cup. 3.4. Let sit for 1 hour. 3.5. Inspect cup for fuel leaks. ⇒ If a leak is present — Fuel contaminated with gasoline» Refer to: Fuel System Cleaning ⇒ If no leak is present & Specific gravity is greater than 51» Refer to: Fuel System Cleaning ⇒ If no leak is present & Specific gravity is between 47–51» Refer to: Fuel Oil Specific Gravity Requirements Table ⇓ If less than 45
- Verify the which fuel is being used according to the Fuel Oil Specific Gravity Requirements Table. For approved fuel types Refer to: Fuel System Specifications ⇒ If usage of incorrect fuel » Replace Fuel — Refer to: Fuel Tank Draining ⇓ If fuel type is correct
- All OK.