My 91 has the same oil cooler lines. They come from the drivers side of the engine and come under the radiator. They then split, one going to the bottom drivers side corner of the A/C condensor/oil cooler and the other goes to the bottom passenger side corner of the A/C condensor/oil cooler. They transition from rubber hoses to aluminum lines just behind the radiator. I have to have a new aluminum line made up for the passenger side because the flare fitting was frozen to the tube and twisted the tube as I was taking the line off the cooler to remove the radiator.
TT = 2007 Jayco Jay Flight 27bh
TV = 2003 Chevrolet Suburban