OEM 2007 Chevrolet Cobalt Timing Chain

2007 Chevrolet Cobalt Parts Questions & Experts Answers

• Q: How to replace the timing chain, sprockets, or tensioner on 2007 Chevrolet Cobalt?

  A: The necessary tools for Timing Chain and sprocket and tensioner replacement include tensioner tool (J 45027). Tensioner tool (J 45027). The Camshaft cover must be removed prior to lifting the vehicle. After removing the engine front cover you should lower the vehicle. A 24 mm open-end wrench should engage the Camshaft flats before you rotate the Camshaft in a clockwise direction. Start by positioning the no. 1 Piston at 60 degrees before top dead center then remove the spark plugs to simplify rotation. Then detach the Timing Chain Tensioner and fixed Timing Chain Guide access plug while extracting the fixed Timing Chain Guide, upper Timing Chain Guide, exhaust Camshaft sprocket bolt (discard), exhaust Camshaft sprocket, Timing Chain tensioner guide, intake Camshaft sprocket bolt (discard), intake Camshaft sprocket, and Timing Chain through the cylinder head opening. Remove the crankshaft sprocket as well as the oil nozzle and bolt and balance shaft drive chain tensioner and adjustable balance shaft chain guide and small balance shaft drive chain guide and upper balance shaft drive chain guide. The balance shaft drive chain removal process becomes easier when all chain slack rests between the crankshaft and water pump sprockets. The initial installation step should involve the upper balance shaft chain guide where bolts require 15 n.m (133 lb in) torque values during tightening. Begin by positioning the balance shaft drive chain with colored links facing the timing marks on sprockets, followed by small balance shaft chain guide installation and adjustable balance shaft drive chain guide attachment (10 N.m (89 lb in) torque). Pressure the tensioner plunger to install the Timing Chain Tensioner (tighten to 10 N.m (89 lb in)). Thread the oil nozzle and bolt to 10 n.m (89 lb in) torque then insert the crankshaft sprocket bearing its 5 o'clock timing mark while lowering the Timing Chain through the cylinder head opening. Before moving on to the next steps, the technician inserts the intake Camshaft sprocket with int diamond pointing to 2 o'clock before tightening a new intake Camshaft sprocket bolt by hand. Then the Timing Chain goes through the sprocket path between the crankshaft and intake Camshaft. The technician also installs the Timing Chain Tensioner guide while torquing to 10 n.m (89 lb in). After setting the exhaust Camshaft sprocket in position at the 10 o'clock exh triangle with the matching colored link attached, hand-tighten a new exhaust Camshaft sprocket bolt and put in the fixed Timing Chain Guide which requires 15 n.m (133 lb in) torque. The Timing Chain Guide bolt access hole plug should receive a layer of sealant before tightening it to a torque value of 90 n.m (59 lb ft). The Timing Chain upper guide requires a torque of 10 n.m (89 lb in) before continuing with tensioner inspections using j 45027-2 and j 45027-1 tools. If necessary, the Piston assembly must be compressed. After cleaning the tensioner bore you must install the compressed Piston assembly which should measure 72 mm (2.83 in) in length before you put in the Timing Chain Tensioner (tighten to 75 N.m (55 lb ft)). After releasing the tensioner use a 24 mm wrench to hold the Camshaft then apply 85 n.m (63 lb ft) torque while rotating the new Camshaft bolts another 30 degrees. After installing the Camshaft cover raise the vehicle to mount the engine front cover then lower the vehicle before connecting the negative Battery Cable.