Engine oil viscosity – ambient temperature Ambient temperature 2.3.9. Oil filter & cooler z Oil filter is assembled to the oil cooler. Oil cooler is plane tube and is cooled by the cooling water . z Check for oil pressure and oil leaks, and repair or replace the oil filter if necessary. z Change the oil filter cartridge Oil filter and cartridge simultaneously at every replacement of engine oil. Oil cooler Oil filter and cartridge DL06 Diesel Engine Technical Information 25