Originally posted by R Pope
Lots of cop cars and taxis have factory oil coolers. The makers don't like them on Joe Citizen grocery getters because they are a potential leak source, and they cost money. The ones in the radiator are better in cold climates because they actually warm the oil faster on a cold start, as do trans coolers in the rad tank. The Ford cop car ones have a bypass in the adapter that lets cold oil reach the engine easier at startup.
lots of cops cars don't have them. cop cars has sirens and blue lights, but I wouldn't put them on my hot rod.