GMC 12686433 Pump Assembly, Oil

The first step to take in order to access the timing chain cover is to needlessly uninstall the oil pan. Next, screw special tool EN-51257 to the engine block, and place one piece of it against the timing chain tensioner, and the other piece against the edge of the body of the oil pump, fastening the mounting bolts in place. Turn the car over and unfasten the oil pump mounting bolt; then, slide the pump off of the crankshaft. Should the oil pump be pulled out without insertion of a new one, then make sure that special tool EN-51267 is secured on the engine block against the pump up to the time of reinsertion; otherwise, the tool warrants a new oil pump. To check, remove the oil pump cover and pull out the rotors of the pump body, clean all the parts with solvent, dry them properly and look fore any damage such as the condition of the bolt holes that has been stripped and the splined surfaces on the crankshaft sprocket. If any of the components are scored, scratched or worn, replace the whole oil pump assembly as the part is not serviceable. For installation turn the pump by hand while pouring clean engine oil into the pick-up tube hole until full. Locate the oil pump atop the end of the crankshaft so that the crankshaft sprocket teeth engage with the oil pump drive teeth inclusive of seating the pump firmly against the block. Apply upward force on the pump body to ensure it makes good contact with tool during the tightening of the bolts and there must be no gap between the oil pump housing and the tool; if there is such gap put the pump against the tool tighten the bolts again. Tighten the mounting bolts of the oil pump to the appropriate torque value, put the timing chain cover in place then the oil pan. Reassemble the engine in the reverse manner to which it was dismantled and fill with oil and coolant where needed, start the engine and check for leakages and oil pressure.

To remove the timing chain cover and, for 6.0L models, the oil pan, start by taking off the oil pump pick-up tube mounting nuts and bolts, then lower the pick-up tube and screen assembly from the vehicle, ensuring to remove the bolt securing the oil pick-up tube to the oil pump. Next, for 6.0L models, take out the oil pump retaining bolts and slide the pump off the end of the crankshaft. For 5.3L and 6.2L models, install special tool EN-51257 against the timing chain tensioner and the edge of the oil pump body, tightening the mounting bolts securely. It is crucial for 5.3L and 6.2L models that if the oil pump is removed without replacement, special tool EN-51267 must be installed to maintain alignment until reinstallation; otherwise, a new oil pump is required. After removing the oil pump cover, withdraw the rotors and clean all components thoroughly, inspecting for damage, particularly on bolt holes and splined surfaces; replace the entire oil pump assembly if any components are scored or worn. To install, prime the pump with clean engine oil while turning it by hand, then position the oil pump over the crankshaft, ensuring proper alignment with the crankshaft sprocket. For 5.3L and 6.2L models, maintain contact between the pump body and the alignment tool while tightening the bolts, ensuring no gap exists. Install and torque the oil pump mounting bolts, then attach a new O-ring to the oil pump pick-up tube, fastening it securely to prevent air from entering the oiling system. Finally, align and install the timing chain cover and oil pan for 6.0L models, complete the installation in reverse order, add oil and coolant as needed, and run the engine to check for leaks and oil pressure.

For 2014 and earlier models, begin by removing the oil pan. While supporting the oil pump, unscrew the bolt holding the oil pump to the rear main bearing cap, then remove the pump. Lower the pump and take it out along with the pump driveshaft, ensuring that the hard nylon sleeve used for alignment is in place on the oil pump driveshaft; if not, check the oil pan for pieces of the sleeve, clean them out, and obtain a new sleeve. Inspect the screen and pickup tube for damage or looseness, ensuring a light fit onto the oil pump. If a new oil pump is being installed, confirm that the pump driveshaft is properly mated with the shaft inside the pump. Position the pump on the engine, aligning the slot in the upper end of the driveshaft with the tang on the lower end of the distributor shaft, as proper mating is essential. Install and tighten the mounting bolt to the specified torque, then reinstall the oil pan. For 2018 and later models, start by removing the timing chain cover and the oil pan. Install special tool EN-51257 against the timing chain tensioner and the edge of the oil pump body, tightening the mounting bolts securely. Remove the oil pump mounting bolts and slide the pump off the crankshaft. If the oil pump is being removed without replacement, ensure that special tool EN-51267 is installed to the engine block and against the pump before removal, remaining in place until reinstallation; failure to do so necessitates installing a new oil pump. Remove the oil pump cover and withdraw the rotors, cleaning the components with solvent, drying them thoroughly, and inspecting for damage, including checking bolt holes and splined surfaces for wear. If any components are scored or worn, replace the entire oil pump assembly. Prime the pump by pouring clean engine oil into the pickup tube hole while turning the pump by hand. Position the oil pump over the crankshaft, aligning the teeth on the crankshaft sprocket with those on the oil pump drive gear, ensuring the pump is fully seated against the block. Push the pump body upward to maintain contact with the tool while tightening the bolts, ensuring no gap exists between the oil pump housing and the tool; if a gap is present, loosen the bolts, push the pump against the tool, and retighten. Install and tighten the oil pump mounting bolts to the specified torque, then align and install the timing chain cover and the oil pan. Complete the installation in reverse order of removal, adding oil and coolant as necessary, running the engine, and checking for leaks and oil pressure.

To have access to the timing chain cover you have to, first of all, safely unbolt and take off the pick-up tube and the screen that is located on it and is called oil pump pick-up tube mounting nuts and bolts. Subsequently, unscrew the oil pump retaining bolts, and pass the pump over the extremity of the crankshaft. For inspection, it is necessary to remove the oil pump cover and take out the rotors from the pump body: clean the parts in solvent and dry them while inspecting the damage, especially the hole on the bolt /crankshaft sprocket and splines. Any component which is scored, scratched or worn should be changed with a new oil pump assembly because no spare parts of this product where available at the time of writing this report. For installation turn the pump by hand and pour some clean motor oil into the pick-up tube hole to prime the pump. In setting the oil pump insert it over the tip of the crankshaft, line up the teeth on the crankshaft sprocket to those on the oil pump drive gear and ensure the pump fits snug on the block. Screw in the oil pump mounting bolts and then torque the bolts to the required strength. On the engine main studs, fit a new O-ring on the oil pump pick-up tube and on the pump, make sure the mounting bolts of the pick-up tube are well tightened so as to minimize air infiltration into the oiling circuit. Two, position and fit the timing chain cover; thereafter, the oil pan and other components will also require reinstallation in a reverse manner to that which they were initially removed from. Then put oil and coolants as required and start the engine to check for leaks as well as the oil pressure.