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.

Install special tool EN-51257 against the timing chain tensioner and the edge of the oil pump body, tightening the mounting bolts securely.

Finally, add oil and coolant as necessary, run the engine, and check for any leaks as well as the oil pressure.

Begin by removing the oil pan.