This invention relates to an integrated module having a provisions of inlet manifold (1), valve cover (2), exhaust gas re circulation, blow by oil separation, oil filling and manifold pressure and temperature sensor mountings, for twin cylinder internal combustion inline common rail diesel engine. Integrated module is basically provided with inlet manifold portion (1) and valve cover (2) portion, said inlet manifold portion (1) is provided with separate openings at intake (3) for supply of fresh air exhaust gases (4). Plenum chamber (5) of inlet manifold portion (1) is provided with a smooth curvilinear surface to ensure smooth flow and uniform distribution of mixture of fresh air and exhaust gases to individual twin, inlet ports of the cylinder head. The twin openings (6) of inlet manifold portion (1) are adopted to be mounted with corresponding twin ports of cylinder head. Separate passage is provided at the entrance of valve cover portion (2) for entry of blow by gases, and said passage is also provided with a valve to control the flow of blow by gases. Valve cover portion (2) is also provided with baffles (3) to separate the oil particles from blow by gases. Separated oil gets collected in the baffle plate (10) provided at cylinder head, while gases without oil contents circulated back in to the charging system through a port provided above the entry port. Inlet manifold portion (1) is provided with mountings for location of pressure and temperature sensors and cylinder head cover is provided with opening for filling the oil to the engine. Sealing profile provided with sealing material on the periphery of said cylinder cover portion of integrated module ensures leak proof sealing between blow by gases and pressurized air with no escape of pressurized air and blow by gases to atmosphere.