The oil filter may be one of three different types, with gear type
Oil Pumps, a bolt-on type filter bowl and separate filter element is used, identifiable as a Mann and Hummel unit by the 7.0 mm diameter oil passage in the upper housing, and the pressure relief valve can be dismantled. With rotor type oil pumps, a bolt-on type filter of Purolator manufacture may be encountered, distinguishable from the Mann and Hummel version by its 12.0 mm diameter oil passage in the upper housing, and the pressure relief valve in this type cannot be dismantled. Later models with rotor type oil pumps utilize a disposable type screw-on filter cartridge in conjunction with a light alloy housing.