G3406 and G3412 Generator Sets Caterpillar

The most accurate check of the oil level is performed when the engine is stopped. Perform this maintenance on a surface that is as level as possible.

Note: For engines with positive crankcase ventilation, remove the oil filler cap. Allow the crankcase pressure to stabilize before checking the engine oil level.

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Illustration 1	g00781190
(1) Oil level gauge (dipstick) (2) Oil filler cap

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Illustration 2	g00735162
(3) "ENGINE STOPPED WITH OIL COLD" side (4) "ENGINE AT LOW IDLE WITH OIL WARM" side (5) "ADD" mark (6) "FULL" mark

1. Ensure that oil level gauge (1) is seated.

   1. If the engine is stopped, remove oil level gauge (1). Observe the oil level on "ENGINE STOPPED" side (3).

   2. If the engine is operating, reduce the engine speed to low idle. Remove oil level gauge (1) and observe the oil level on "LOW IDLE" side (4).

      The oil level should be between "ADD" mark (5) and "FULL" mark (6).

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   NOTICE
   Engine damage can occur if the crankcase is filled above the "FULL" mark on the oil level gauge (dipstick). An overfull crankcase can cause the crankshaft to dip into the oil. This will reduce the power that is developed and also force air bubbles into the oil. These bubbles (foam) can cause the following problems: reduction of the oil's ability to lubricate, reduction of oil pressure, inadequate cooling, oil blowing out of the crankcase breathers and excessive oil consumption. Excessive oil consumption will cause deposits to form on the pistons and in the combustion chamber. Deposits in the combustion chamber lead to the following problems: guttering of the valves, packing of carbon under the piston rings and wear of the cylinder liner. If the oil level is above the "FULL" mark on the oil level gauge, drain some of the oil immediately.

2. If necessary, remove oil filler cap (2) and add oil. For the correct oil to use, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" topic. Do not fill the crankcase above "FULL" mark (6). Clean the oil filler cap. Install the oil filler cap.

3. Record the amount of oil that is added. For the next oil sample and analysis, include the total amount of oil that has been added since the previous oil change. This will help to provide the most accurate oil analysis.