jimmy57 wrote:it is a parallel plate cooler. It is configured as though you took a radiator and sealed the finned area where air normally passes and pushed oil through the radiator. Of course, now the radiator coolant absorbs heat instead of giving up heat. The oil from oil pump passes through filter and then goes through oil cooler before returning to go to crank, cams, turbo.
The coolers integrated in tank of radiator work this way too with a little modification. Those have the oil going through a mini radiator that sits in the hot end of radiator. Auto trans cooler gets the cold end.
So, if this is closed, no fins exchanger, the oil, in the beginning of the engine operation, is being warmed up (not cooled) by the coolant which heats up much faster than the engine oil. The thermostat, I believe, is just a plunger and a spring, that allows the oil circulate through the heat exchanger while it is cold and thick, and then, when the oil loses some viscosity during warm up, the plunger closes and there is no more circulation through that heat exchanger in the radiator. I think it makes sense as it keeps condensation from the intercooler down to the minimum during short urban trips in the cool weather.Just my theory.Any opinions?