A matter which has puzzled me for some time is the operation of the oil cooler bypass valve in the 4D56 diesel motor (Gen 1 Pajero). The bypass valve extends when it gets hot and actually blocks off the passage of the oil to the cooler radiator and allows more oil to run round the bearings. I would have thought that it would open the passage to the oil cooler so the oil could be cooled quicker but that is not the case. Can anyone explain how the valve works?
1986 Mark 1 Pajero 2.5L turbo diesel station wagon
1993 220si Toyota Camry saloon auto
1993 220si Toyota Camry saloon auto