When the crankshaft pulley is loose, so is the crankshaft sprocket, the engine thus being out of time. A lot of careful attention should be paid to retiming the engine, which must be done strictly in accordance with all the necessary steps of installation in order to prevent severe damage to the engine. Two special tools are required: the camshaft position tool no. 303-1565 for pre-2018 Saturn Sky or the no. 303-1686 for 2019 Saturn Sky and the timing pin #303-507. Firstly, the drivebelt should be undid and the fasteners of the right driveaxle intermediate shaft bracket. For 2015 and later models use the service tool no 303-1686 for the 2014 use models or any for the 2014 and earlier models position the engine and set it to TDC using the relevant tools. Disconnect both camshaft position sensors so getting a view of the camshaft trigger wheels; insert the service tools in the sensor's opening. Tighten the pulley bolt with a torque wrench to a maximum of 300 N.m while holding the crankshaft non-rotating, you will need a strap wrench and an impact gun to remove it. Upon the elimination of the pulley and diamond washer, place a new diamond washer on the crankshaft, apply a thin layer of clean engine oil to the front seal, then place the crankshaft pulley. For 2014 and earlier models, screw in the CKP sensor alignment tool and put a new pulley bolt and for 2015 and later models align the pulley with the guide hole and tighten bolt. Cautiously, but progressively, torque the pulley bolt without the use of the impact gun; uncouple the timing pin, and also, elimination of all the tools used for alignment purposes. Turn the engine in a clockwise direction 2 full revolutions feeling for any resistance and arrive at TDC once again. Place the timing pin into the cylinder block, check the position of the cam shafts using the tool and ensure that the correct engine timing is gotten to. Last, eliminate all the applied alignment tools and bolts, put the timing pin plug back into its proper place, as well as put back all the other components which were removed in the previous steps.