3126 slotEnsure that the bearing tab engages with the slot in connecting rod cap (4) . 3.Place clean engine oil on the pistons, the piston rings, the cylinder bore, the upper half of the connecting rod bearing, and the lower half ofThe Cat 3126 diesel engine is an in six-cylinder engine with a displacement of 7.2 liters. It features a four-stroke cycle and utilizes direct injection for efficient fuel combustion.