GM 91177260
Timing Belt

The first step to replace a Timing Belt requires removal of the Crankshaft Pulley followed by the air cleaner assembly. Remove the Timing Belt cover through the removal of its 8 bolts and single nut. Apply a crankshaft turn to align the timing marks before taking out the Timing Belt. Start by having both upper timing marks (1, 2) correctly positioned before you release the tensioner bolt of the Timing Belt and its associated stud. Use your finger to completely push up the tensioner plate before taking the belt off its positions on the crankshaft and camshaft Timing Belt pulleys. Independent turning of the camshaft and crankshaft after belt removal poses serious risks for equipment damage. The procedure entails removing the tensioner along with its plate, the tensioner spring and spring damper then thoroughly inspect the Timing Belt for signs of wear and cracks before replacement while testing the tensioner's smooth rotation. Start installation by putting the tensioner plate lug into the Timing Belt Tensioner hole of the belt tensioner. Mount the tensioner and tensioner plate onto the cylinder block using a single bolt along with one stud while keeping the fasteners loose. The proper alignment between the tensioner plate movement and tensioner movement relies on a correct tensioner plate lug insertion into the Timing Belt Tensioner hole. Align the punch mark on the crankshaft Timing Belt pulley with the arrow mark on the oil pump case and set the mark from the camshaft Timing Belt pulley to the v on the Timing Belt cover . Install the Timing Belt by aligning its arrow mark with the rotating direction of the crankshaft while maintaining proper timing marks alignment. Install the Timing Belt and tensioner spring after pushing up the tensioner plate while preventing belt slack. Turn the crankshaft clockwise by two full rotations prior to hand-tightening the tensioner stud. The engine requires tightening the Timing Belt Tensioner stud to 11 nm (97 inch lbs.) with the tensioner bolt receiving 25 nm (18 ft. Lbs.) torque. You must check the timing marks alignment before installing the Timing Belt cover with its 8 bolts and 1 nut and applying torque of 11 nm (97 inch lbs.). Screw back the Crankshaft Pulley together with the air cleaner assembly into its original position.

Starting the Timing Belt replacement requires removing the Crankshaft Pulley before separating the retaining clips together with engine wiring harness from the Timing Belt cover. Remove the coolant pump pulley before starting the process of removing 1 nut and 8 bolts which secure the Timing Belt cover. Then take the cover off the vehicle. Disassemble the Timing Belt only when the crankshaft is rotated clockwise while maintaining alignment between the timing marks on both the camshaft gear at points 1 and 4 and the Crankshaft Gear at points 2 and 3. After the Timing Belt removal prevents independent rotation of the camshaft and crankshaft because such action would lead to potential equipment damage. Push upward on the tensioner plate manually then take the Timing Belt off both timing gears of the crankshaft and camshaft after loosening the tensioner bolt and stud. Checking the Timing Belt Tensioner for proper function leads to replacement if the mechanism shows signs of malfunction. You must inspect how the plate operates with the tensioner and verify that the camshaft timing gear displays the v mark on the cylinder head cover while the crankshaft timing gear features the arrow mark on the oil pump case . During Timing Belt installation position the arrow mark to match the rotating direction of the crankshaft so the number 1 piston rests at top dead center in compression stroke. The Timing Belt must be installed on both pulleys with tensioner plate pushed upward until the drive side exhibits no slack. First install the tensioner spring with its spring damper. Then tighten only the tensioner stud manually. The crankshaft should receive one and a half clockwise rotations to reduce slack which requires tightening the Timing Belt Tensioner stud to 11 nm (97 inch lbs.) while the tensioner bolt needs tightening to 27 nm (20 ft. Lbs.). A turn of 180 degrees clockwise on the crankshaft will help confirm proper alignment between the markings on the camshaft (1,4) and the crankshaft (2,3). Install the Timing Belt cover only when you verify the seal position between the coolant pump and oil pump case. Finally, tighten the Timing Belt cover by using the eight bolts and one nut to a torque of 11 nm (97 inch lbs.) install the coolant pump pulley by securing its four bolts to 24 nm (18 ft. Lbs.) and then add the Crankshaft Pulley.