Q: How to properly install and service the oil cooler and its components for 6.0L and 8.1L engines on GMC Yukon?
A: The Oil Cooler, which can be built into the Radiator or placed separately before it, has serviceable lines and hoses for the cooler. Start with the removal of the plastic caps from the quick connect fittings, pull back along the pipe. Clasp one end of the retaining clip with your hands and use a small pick-like tool or bent screwdriver to carefully pry off the opposite end from the quick connect fitting, rotate it and unfasten the entire clip and throw it away. For vehicles having a 6.0l engine, open the Oil Cooler hose clip in the fan shroud. Remove the hoses out of the clip and remove the hoses out of the quick connect of Radiator fittings. Lift the car and then undo the exhaust manifold pipe nuts and relocate the pipe. For 8.1l engine cars, disconnect the Oil Cooler hoses from the clip, pull the pipe fittings straight out, and take the vehicle off and support it. Take out the engine shield bolts and the shield itself if present. For the 6.0l engine, remove hose assembly bracket bolt and bracket bolts for Oil Cooler , this then takes out hose assembly and gasket discarding it but paying attention to the fittings and hoses for abuse. For the 8.1l engine, there is a hose bracket bolt that must be removed, quick connect fittings at the engine that are also removed along with the hose assembly and rocated along with the gasket is discarded and checked for damage. But you are to get a distinct snap during the installation while you are putting together the ends of the tube of the hose assembly with the quick connectors, test by pulling strongly in hardest to verify that the hose assembly is fully inserted. For the 8 1l engine, process the quick connect fittings at the engine, fasten the hose bracket bolt, and tighten it to 50 nm (37 ft. Lbs.). For 6.0l engine, fit in the hose assembly in addition to a new gasket; tighten the adapter bolts to (12 Nm (106 inch lbs.)) & hose bracket bolt to (25 Nm (18 ft. Lbs.)) mounting the engine shield and bolts if fitted with bolt to 20-nm (15 ft. Lbs.). Install the new retaining clip on the quick connect fitting properly using your thumb and forefinger pressing it engaged in all three slots and turning it in. Mount a new retaining clip to the remaining fitting, insert the pipe to the exhaust manifold, and tighten the nuts to 50 nm (37 ft. Lbs.). Lower the vehicle, then attach the hoses to the clip on the fan shroud and snap it shut, making sure there is a plastic end on the cooler line that goes into the fitting. For the 8.1l engine, install the hoses to the clip, connect the lines to the Radiator, and be sure the line is fully inserted into the quick connect fitting while there is a click that is heard or felt, followed by a sharp pull back to ensure that it is installed. Finally, place on the snap plastic cap to the fitting ensuring it's seated in place with even the smallest gap between the cap and the fitting.