The SAE grade number indicates the viscosity of the engine oil, or its ability to lubricate under a given temperature. The lower the SAE grade number, the lighter the oil; the lower the viscosity, the easier it is to crank the engine in cold weather.
The API (American Petroleum Institute) designation indicates the classification of engine oil for use under given operating conditions. Only oils designated for Service SG should be used to provide maximum engine protection. Both the SAE grade number and the API designation can be found on the container.
Non-detergent or straight mineral oils should not be used.
Oil viscosities should be chosen from those oils recommended for the lowest anticipated temperatures during the oil change interval.
OIL LEVEL CHECK
See Figures 1, 2 and 3
When checking the oil level, it is best that the oil be at operating temperature, although checking the level immediately after stopping will give a false reading because all of the oil will not have drained back into the crankcase. Be sure that the truck is on a level surface, allowing tine for all of the oil to drain back into the crankcase.
- Open the hood and locate the engine oil dipstick.
- Remove the dipstick and wipe it clean with a rag.
- Insert the dipstick fully into the tube and remove it again. Hold the dipstick horizontal and read the level on the dipstick. The level should be between the F (Full) and L (Low) marks. If the oil level is at or below the L mark, sufficient oil should be added to restore the level to the proper place. Oil is added through the capped opening in the top of the valve cover. See the information on "Oil and Fuel Recommendations'' for the proper viscosity and oil to use.
- Replace the dipstick and check the level after adding oil. Be careful not to overfill the crankcase.
OIL AND FILTER CHANGE
See Figures 4 through 13
The engine oil and filter should always be changed together. To skip an oil filter change is to leave a quart of contaminated oil in the engine. Engine oil and filter should be changed according to the schedule in the Maintenance Intervals chart.Under conditions such as:
the oil change interval and filter replacement interval should be cut in half. Operation of the engine in severe conditions, such as a dust storm, may require an immediate oil and filter change.
To change the engine oil and filter, the truck should be parked on a level surface and the engine should be at operating temperature. This is to ensure that foreign matter will be drained away with the oil and not left behind in the engine to form sludge, which will happen if the engine is drained cold. Oil that is slightly brownish when drained is a good sign that the contaminants are being drained away. You should have available a container that will hold at least five quarts, a wrench to fit the oil drain plug, a spout for pouring in new oil and some rags to clean up the inevitable mess. If the filter is being replaced, you will also need a band wrench to fit the filter.
- Position the truck on a level surface and set the parking brake or block the wheels. Slide a drain pan under the oil drain plug.
- From under the truck, loosen, but do not remove the oil drain plug. Cover your hand with a heavy rag or glove and slowly unscrew the drain plug. Push the plug against the threads to prevent oil from leaking past the threads.
- As the plug comes to the end of the threads, whisk it away from the hole, letting the oil drain into the pan, which hopefully is still under the drain plug. This method usually avoids the messy task of reaching into a tub full of hot, dirty oil to retrieve a usually elusive drain plug. Crawl out from under the truck and wait for the oil to drain.
- When the oil is drained, install the drain plug.
- Change the engine oil filter as necessary or desired. Loosen the filter with a band wrench and spin the filter off by hand. Be careful of the one quart of hot, dirty oil that inevitably overflows the filter.
- Coat the rubber gasket on a new filter with engine oil and install the filter. Screw the filter onto the mounting stud and tighten according to the directions on the filter.
- Refill the engine with the specified amount of clean engine oil. Be sure to use the proper viscosity. Pour the oil in through the capped opening.
- Run the engine for several minutes, checking for oil pressure and leaks. Check the level of the oil and add if necessary.
Take the drained oil, in a suitable container, to your local service station, or a special designated oil recycling station for disposal.